Integrated Taxonomic Information System - Taxon Author Search Results

Taxon author: S. Watson

ITIS records citing taxon author "S. Watson"
 
 Kingdom Animalia
  Uperoleia altissima Davies, Watson, McDonald, Trenerry and Werren, 1993 -- valid
 
 Kingdom Plantae
  Abronia maritima Nutt. ex S. Watson -- accepted -- red sand verbena
  Abronia nana S. Watson -- accepted -- dwarf sand verbena
  Abronia nana var. nana S. Watson -- accepted -- dwarf sand verbena
  Abronia turbinata Torr. ex S. Watson -- accepted -- transmontane sand verbena
  Abronia villosa S. Watson -- accepted -- desert sand verbena
  Abronia villosa var. villosa S. Watson -- accepted -- desert sand verbena, woolly desert sand verbena
  Abutilon berlandieri A. Gray ex S. Watson -- accepted -- Berlandier's Indian mallow
  Abutilon malacum S. Watson -- accepted -- yellow Indian mallow
  Abutilon newberryi S. Watson -- not accepted
  Abutilon parishii S. Watson -- accepted -- Parish's Indian mallow
  Abutilon reventum S. Watson -- accepted -- yellowflower Indian mallow
  Acacia millefolia S. Watson -- not accepted -- milfoil wattle, Santa Rita acacia
  Acacia schaffneri (S. Watson) F.J. Herm. -- not accepted -- Schaffner's wattle, twisted acacia
  Acacia schaffneri var. schaffneri (S. Watson) F.J. Herm. -- not accepted -- Schaffner's wattle
  Acalypha pringlei S. Watson -- not accepted
  Achnatherum occidentale (Thurb. ex S. Watson) Barkworth -- accepted -- western needlegrass
  Achnatherum occidentale ssp. occidentale (Thurb. ex S. Watson) Barkworth -- accepted -- western needle grass, western needlegrass
  Acmispon nevadensis (S. Watson) Brouillet -- accepted -- Nevada bird's-foot trefoil
  Acmispon nevadensis var. nevadensis (S. Watson) Brouillet -- accepted -- Nevada bird's-foot trefoil
  Acnida altissima var. subnuda (S. Watson) Fernald -- not accepted
  Acnida floridana S. Watson -- not accepted
  Acnida subnuda (S. Watson) Standl. -- not accepted
  Acrolasia dispersa (S. Watson) Davidson -- not accepted
  Actaea arizonica (S. Watson) J. Compton -- accepted -- Arizona bugbane
  Actaea laciniata (S. Watson) J. Compton -- accepted -- Mt. Hood bugbane
  Adenostoma fasciculatum var. obtusifolium S. Watson -- accepted -- chamise
  Adolphia californica S. Watson -- accepted -- California adolphia, California prickbush
  Agrostis exarata var. microphylla S. Watson ex Vasey -- not accepted
  Aklema plicata (S. Watson) Millsp. -- not accepted
  Aletes bipinnata (S. Watson) W.A. Weber -- not accepted
  Aletes nivalis (S. Watson) W.A. Weber -- not accepted
  Aletes parryi (S. Watson) W.A. Weber -- not accepted
  Aliciella latifolia (S. Watson) J.M. Porter -- accepted -- broad-leaf gilia
  Aliciella latifolia ssp. latifolia (S. Watson) J.M. Porter -- accepted -- broadleaf gilia
  Allenrolfea occidentalis (S. Watson) Kuntze -- accepted -- iodinebush
  Allionia glabra (S. Watson) Kuntze -- not accepted
  Allium atrorubens S. Watson -- accepted -- dark red onion, darkred onion, red onion
  Allium atrorubens var. atrorubens S. Watson -- accepted -- darkred onion
  Allium atrorubens var. cristatum (S. Watson) McNeal -- accepted -- darkred onion, Wild onion
  Allium bidwelliae S. Watson -- not accepted
  Allium bigelovii S. Watson -- accepted -- Bigelow onion, Bigelow's onion
  Allium bisceptrum S. Watson -- accepted -- aspen onion, twincrest onion
  Allium bisceptrum var. bisceptrum S. Watson -- not accepted -- twincrest onion
  Allium bisceptrum var. palmeri (S. Watson) Cronquist -- not accepted -- aspen onion
  Allium bolanderi S. Watson -- accepted -- Bolander's onion
  Allium bolanderi var. bolanderi S. Watson -- accepted -- Bolander's onion
  Allium brandegeei S. Watson -- accepted -- Brandegee's onion
  Allium brevistylum S. Watson -- accepted -- shortstyle onion
  Allium breweri S. Watson -- not accepted
  Allium campanulatum S. Watson -- accepted -- dusky onion, Sierra onion
  Allium campanulatum var. bidwelliae (S. Watson) Jeps. -- not accepted
  Allium collinum Douglas ex S. Watson -- not accepted
  Allium cristatum S. Watson -- not accepted
  Allium cusickii S. Watson -- not accepted
  Allium douglasii var. nevii (S. Watson) Ownbey & Mingrone -- not accepted
  Allium fimbriatum S. Watson -- accepted -- fringed onion
  Allium fimbriatum ssp. parryi (S. Watson) Traub & Ownbey -- not accepted
  Allium fimbriatum var. fimbriatum S. Watson -- accepted -- fringed onion
  Allium fimbriatum var. parryi (S. Watson) Ownbey & Aase -- not accepted
  Allium geyeri S. Watson -- accepted -- Geyer onion, Geyer's onion
  Allium geyeri var. geyeri S. Watson -- accepted -- Geyer onion, Geyer's onion
  Allium haematochiton S. Watson -- accepted -- redskin onion
  Allium lacunosum S. Watson -- accepted -- pitted onion
  Allium lacunosum var. lacunosum S. Watson -- accepted -- pitted onion
  Allium lemmonii S. Watson -- accepted -- Lemmon onion, Lemmon's onion
  Allium macrum S. Watson -- accepted -- rock onion
  Allium madidum S. Watson -- accepted -- swamp onion
  Allium nevadense S. Watson -- accepted -- Nevada onion
  Allium nevadense var. cristatum (S. Watson) Ownbey -- not accepted
  Allium nevadense var. cristatum (S. Watson) Ownbey -- not accepted
  Allium nevadense var. nevadense S. Watson -- not accepted -- Nevada onion
  Allium nevii S. Watson -- accepted -- Nevius' garlic
  Allium nuttallii S. Watson -- not accepted
  Allium palmeri S. Watson -- not accepted
  Allium parishii S. Watson -- accepted -- Parish's onion
  Allium parryi S. Watson -- accepted -- Parry's fringed onion
  Allium platycaule S. Watson -- accepted -- broadstem onion, broadstemmed onion
  Allium pleianthum S. Watson -- not accepted -- manyflower onion
  Allium plummerae S. Watson -- accepted -- Tanners Canyon onion
  Allium scilloides Douglas ex S. Watson -- accepted -- fragile onion
  Allium serratum S. Watson -- not accepted -- pompom onion
  Allium tribracteatum var. andersoni S. Watson -- not accepted
  Allium tribracteatum var. andersonii S. Watson -- not accepted
  Allium validum S. Watson -- accepted -- Pacific onion, swamp onion
  Alnus incana var. virescens S. Watson -- not accepted
  Alternanthera palmeri (S. Watson) -- not accepted -- Palmer's joyweed
  Amaranthus blitoides S. Watson -- accepted -- mat amaranth, prostrate amaranth, prostrate pigweed
  Amaranthus californicus (Moq.) S. Watson -- accepted -- California amaranth, California pigweed
  Amaranthus chihuahuensis S. Watson -- accepted -- Chihuahuan amaranth
  Amaranthus fimbriatus (Torr.) Benth. ex S. Watson -- accepted -- fringed amaranth, fringed pigweed
  Amaranthus fimbriatus var. fimbriatus (Torr.) Benth. ex S. Watson -- not accepted -- fringed amaranth, fringed pigweed
  Amaranthus floridanus (S. Watson) J.D. Sauer -- accepted -- Florida amaranth
  Amaranthus greggii S. Watson -- accepted -- Gregg's amaranth
  Amaranthus leucocarpus S. Watson -- not accepted
  Amaranthus palmeri S. Watson -- accepted -- carelessweed, Palmer's amaranth
  Amaranthus powellii S. Watson -- accepted -- Powell's amaranth, Powell's pigweed
  Amaranthus powellii ssp. powellii S. Watson -- not accepted -- Powell's amaranth
  Amaranthus pringlei S. Watson -- not accepted -- Pringle's amaranth
  Amaranthus retroflexus var. powellii (S. Watson) B. Boivin -- not accepted
  Amaranthus torreyi auct. non (A. Gray) Benth. ex S. Watson -- not accepted
  Amaranthus torreyi auct. non (A. Gray) Benth. ex S. Watson -- not accepted
  Amaranthus torreyi (A. Gray) Benth. ex S. Watson -- accepted -- Torrey's amaranthus
  Amaranthus tuberculatus var. subnudus (S. Watson) Mohlenbr. -- not accepted
  Amaranthus venulosus S. Watson -- not accepted -- fringed amaranth
  Amaranthus wrightii S. Watson -- accepted -- Wright's amaranth
  Amerosedum debile (S. Watson) Á. Löve & D. Löve -- not accepted
  Amerosedum divergens (S. Watson) Á. Löve & D. Löve -- not accepted
  Amerosedum radiatum (S. Watson) Á. Löve & D. Löve -- not accepted
  Ammoselinum butleri (Engelm. ex S. Watson) J.M. Coult. & Rose -- accepted -- Butler's sandparsley
  Amphiscirpus nevadensis (S. Watson) Oteng-Yeb. -- accepted -- Nevada bulrush
  Amyris madrensis S. Watson -- accepted -- mountain torchwood
  Androstephium breviflorum S. Watson -- accepted -- pink funnel lily, pink funnellily, smallflower androstephium
  Anemone drummondii S. Watson -- accepted -- Drummond's anemone
  Anemone drummondii ssp. drummondii S. Watson -- not accepted -- Drummond's anemone
  Anemone drummondii var. drummondii S. Watson -- accepted -- Drummond's anemone
  Anemone occidentalis S. Watson -- accepted -- white pasqueflower
  Angelica dawsonii S. Watson -- accepted -- Dawson's angelica
  Angelica kingii (S. Watson) J.M. Coult. & Rose -- accepted -- King's angelica
  Angelica lyallii S. Watson -- not accepted
  Angelica pinnata S. Watson -- accepted -- small-leaf angelica, smallleaf angelica
  Angelica tomentosa S. Watson -- accepted -- woolly angelica
  Angelica tomentosa var. tomentosa S. Watson -- not accepted -- woolly angelica
  Angelica wheeleri S. Watson -- accepted -- Utah angelica
  Anhalonium furfuraceum (S. Watson) J.M. Coult. -- not accepted
  Anoda reticulata S. Watson -- accepted -- netted anoda
  Antigonon flavescens S. Watson -- accepted -- lovechain
  Antirrhinum kingii S. Watson -- not accepted
  Aphyllon dugesii S. Watson -- not accepted
  Apium echinatum (Nutt. ex DC.) Benth. & Hook. f. ex S. Watson -- not accepted
  Aquilegia flavescens S. Watson -- accepted -- yellow columbine
  Aquilegia flavescens var. flavescens S. Watson -- not accepted -- yellow columbine
  Aquilegia formosa var. flavescens (S. Watson) M. Peck -- not accepted
  Aquilegia longissima A. Gray ex S. Watson -- accepted -- long spur columbine, longspur columbine
  Arabis arcuata var. perennans (S. Watson) M.E. Jones -- not accepted
  Arabis arcuata var. subvillosa S. Watson -- not accepted
  Arabis arenicola var. pubescens auct. non (S. Watson) Gelert -- not accepted
  Arabis beckwithii S. Watson -- not accepted -- Beckwith's rockcress
  Arabis bolanderi S. Watson -- not accepted
  Arabis breweri S. Watson -- not accepted -- Brewer's rockcress
  Arabis breweri var. breweri S. Watson -- not accepted -- Brewer's rockcress
  Arabis confinis S. Watson -- not accepted
  Arabis cusickii S. Watson -- not accepted -- Cusick's rockcress
  Arabis fendleri (S. Watson) Greene -- not accepted -- fendler rockcress, Fendler's rockcress
  Arabis fendleri var. fendleri (S. Watson) Greene -- not accepted -- Fendler's rockcress
  Arabis fernaldiana var. stylosa (S. Watson) Rollins -- not accepted -- park rockcress
  Arabis furcata S. Watson -- accepted -- Columbia Gorge rockcress
  Arabis furcata var. furcata S. Watson -- not accepted -- Columbia Gorge rockcress
  Arabis holboellii var. fendleri S. Watson -- not accepted
  Arabis howellii S. Watson -- not accepted
  Arabis lemmonii S. Watson -- not accepted -- Lemmon rockcress, Lemmon's rockcress
  Arabis lemmonii var. lemmonii S. Watson -- not accepted -- Lemmon's rockcress
  Arabis lyallii S. Watson -- not accepted -- Lyall's rockcress
  Arabis lyallii var. lyallii S. Watson -- not accepted -- Lyall's rockcress
  Arabis macounii S. Watson -- not accepted
  Arabis microphylla var. macounii (S. Watson) Rollins -- not accepted -- Macoun's rockcress
  Arabis parishii S. Watson -- not accepted -- dwarf rockcress, Parish's rockcress
  Arabis perennans S. Watson -- not accepted -- perennial rockcress
  Arabis platysperma var. howellii (S. Watson) Jeps. -- not accepted -- Howell's pioneer rockcress
  Arabis pulchra M.E. Jones ex S. Watson -- not accepted -- beautiful rockcress, beauty rockcress
  Arabis pulchra var. pulchra M.E. Jones ex S. Watson -- not accepted -- beautiful rockcress, desert rockcress
  Arabis repanda S. Watson -- not accepted -- Repand's rockcress, Yosemite rockcress
  Arabis repanda var. repanda S. Watson -- not accepted -- Yosemite rockcress
  Arabis sparsiflora var. subvillosa (S. Watson) Rollins -- not accepted -- hairystem rockcress
  Arabis subpinnatifida S. Watson -- not accepted -- Klamath rockcress
  Arabis suffrutescens S. Watson -- not accepted -- woody rockcress
  Arabis suffrutescens var. suffrutescens S. Watson -- not accepted -- woody rockcress
  Aralia californica S. Watson -- accepted -- California spikenard
  Arenaria aculeata S. Watson -- not accepted -- prickly sandwort, spiny sandwort
  Arenaria congesta var. aculeata (S. Watson) M.E. Jones -- not accepted
  Arenaria congesta var. kingii (S. Watson) B.L. Rob. -- not accepted
  Arenaria congesta var. macradenia (S. Watson) M.E. Jones -- not accepted
  Arenaria congesta var. subcongesta (S. Watson) S. Watson -- not accepted -- ballhead sandwort, loosehead sandwort
  Arenaria fendleri var. aculeata (S. Watson) S.L. Welsh -- not accepted
  Arenaria fendleri var. glabrescens S. Watson -- not accepted
  Arenaria fendleri var. subcongesta S. Watson -- not accepted
  Arenaria howellii S. Watson -- not accepted -- Howell's sandwort
  Arenaria kingii (S. Watson) M.E. Jones -- not accepted -- King's sandwort
  Arenaria kingii ssp. kingii (S. Watson) M.E. Jones -- not accepted -- King's sandwort
  Arenaria kingii var. glabrescens (S. Watson) Maguire -- not accepted
  Arenaria macradenia S. Watson -- not accepted -- Mojave sandwort, shrubby sandwort
  Arenaria macradenia ssp. macradenia S. Watson -- not accepted -- Mojave sandwort
  Arenaria macradenia ssp. macradenia var. macradenia S. Watson -- not accepted -- Mojave sandwort
  Arenaria macradenia var. macradenia S. Watson -- not accepted -- Mojave sandwort
  Arenaria pusilla S. Watson -- not accepted
  Arenaria subcongesta (S. Watson) Rydb. -- not accepted
  Arenaria verna var. rubella (Wahlenb.) S. Watson -- not accepted
  Aristida fugitiva Vasey ex S. Watson -- not accepted
  Aristolochia brevipes var. acuminata S. Watson -- not accepted
  Artemisia dracunculoides var. dracunculina (S. Watson) S.F. Blake -- not accepted
  Artemisia forwoodii S. Watson -- not accepted
  Artemisia glauca var. dracunculina (S. Watson) Fernald -- not accepted
  Artemisia glauca var. dracunculus (S. Watson) Fernald -- not accepted
  Asarum hartwegii S. Watson -- accepted -- Hartweg's wildginger
  Asarum lemmonii S. Watson -- accepted -- Lemmon's wildginger
  Asclepias albicans S. Watson -- accepted -- candelilla, wax milkweed, whitestem milkweed
  Asclepias cryptoceras S. Watson -- accepted -- cow cabbage, Humboldt milkweed, Humboldt Mountains milkweed, pallid milkweed
  Asclepias cryptoceras ssp. cryptoceras S. Watson -- accepted -- cow cabbage, pallid milkweed
  Aster forwoodii S. Watson -- not accepted
  Astragalus accidens S. Watson -- accepted -- Rogue River milkvetch
  Astragalus accidens var. accidens S. Watson -- accepted -- Rogue River milkvetch
  Astragalus acutirostris S. Watson -- accepted -- sharpkeel milkvetch
  Astragalus ampullarius S. Watson -- accepted -- gumbo milk-vetch
  Astragalus antisellii A. Gray ex W.H. Brewer & S. Watson -- not accepted
  Astragalus atratus S. Watson -- accepted -- mourning milkvetch
  Astragalus atratus var. atratus S. Watson -- accepted -- mourning milkvetch
  Astragalus austiniae A. Gray ex W.H. Brewer & S. Watson -- accepted -- Austin's milkvetch
  Astragalus bigelovii var. matthewsii (S. Watson) M.E. Jones -- not accepted
  Astragalus bigelovii var. thompsoniae (S. Watson) M.E. Jones -- not accepted
  Astragalus calycosus Torr. ex S. Watson -- accepted -- matted poison milkvetch, mattedmilkvetch, Torrey's milkvetch
  Astragalus calycosus var. calycosus Torr. ex S. Watson -- accepted -- Torrey milkvetch, Torrey's milkvetch
  Astragalus canadensis var. mortonii (Nutt.) S. Watson -- accepted -- Morton's Canadian milkvetch
  Astragalus castaneiformis S. Watson -- accepted -- chestnut milk-vetch, chestnut milkvetch
  Astragalus congdonii S. Watson -- accepted -- Congdon's milkvetch
  Astragalus conjunctus S. Watson -- accepted -- Idaho milkvetch
  Astragalus conjunctus var. conjunctus S. Watson -- accepted -- Idaho milkvetch
  Astragalus diaphanus var. diurnus (S. Watson) Barneby ex M. Peck -- not accepted
  Astragalus diurnus S. Watson -- not accepted
  Astragalus episcopus S. Watson -- accepted -- bishop's milkvetch
  Astragalus episcopus var. episcopus S. Watson -- not accepted -- Bishop milkvetch, bishop's milkvetch
  Astragalus forwoodii S. Watson -- not accepted
  Astragalus forwoodii var. forwoodii S. Watson -- not accepted
  Astragalus frigidus var. americanus (Hook.) S. Watson -- not accepted
  Astragalus giganteus S. Watson -- accepted -- giant loco, giant milkvetch
  Astragalus grayi Parry ex S. Watson -- accepted -- Gray's milkvetch
  Astragalus hypoxylus S. Watson -- accepted -- Huachuca milk-vetch, Huachuca Mountain milkvetch
  Astragalus iodanthus S. Watson -- accepted -- Humboldt River milkvetch
  Astragalus iodanthus var. iodanthus S. Watson -- accepted -- Humboldt River milkvetch
  Astragalus jejunus S. Watson -- accepted -- starveling milkvetch
  Astragalus jejunus var. jejunus S. Watson -- not accepted -- starveling milkvetch
  Astragalus kentrophyta ssp. elatus (S. Watson) W.A. Weber -- not accepted
  Astragalus kentrophyta var. elatus S. Watson -- accepted -- tall spiny milkvetch
  Astragalus kentrophyta var. tegetarius (S. Watson) M.E. Jones -- accepted -- mat milkvetch
  Astragalus lectulus S. Watson -- not accepted
  Astragalus lentiginosus var. fremontii (A. Gray ex Torr.) S. Watson -- accepted -- Fremont's milkvetch
  Astragalus leucolobus S. Watson ex M.E. Jones -- accepted -- Bear Valley milkvetch, Bear Valley wooly-pod, whitepod milkvetch
  Astragalus matthewsii S. Watson -- not accepted
  Astragalus megacarpus var. parryi A. Gray ex S. Watson -- not accepted
  Astragalus menziesii ssp. virgatus (A. Gray ex W.H. Brewer & S. Watson) Abrams -- not accepted
  Astragalus misellus S. Watson -- accepted -- pauper milkvetch
  Astragalus misellus var. misellus S. Watson -- accepted -- pauper milkvetch
  Astragalus mohavensis S. Watson -- accepted -- Mojave milkvetch
  Astragalus mohavensis var. mohavensis S. Watson -- accepted -- Mojave milkvetch
  Astragalus mollissimus var. matthewsii (S. Watson) Barneby -- accepted -- Matthews' woolly locoweed, Matthews' woolly milkvetch, woolly locoweed
  Astragalus mollissimus var. thompsoniae (S. Watson) Barneby -- accepted -- Thompson woolly milkvetch, Thompson's woolly locoweed, Thompson's woolly milkvetch, woolly locoweed
  Astragalus nuttallii var. virgatus (A. Gray ex W.H. Brewer & S. Watson) Barneby -- accepted -- Nuttall's milkvetch
  Astragalus obscurus S. Watson -- accepted -- arcane milkvetch
  Astragalus occidentalis (S. Watson) M.E. Jones -- not accepted
  Astragalus oophorus S. Watson -- accepted -- egg milkvetch
  Astragalus oophorus var. oophorus S. Watson -- accepted -- egg milkvetch
  Astragalus porrectus S. Watson -- accepted -- Lahontan milkvetch
  Astragalus pterocarpus S. Watson -- accepted -- wing milkvetch, winged milkvetch
  Astragalus purshii var. lectulus (S. Watson) M.E. Jones -- accepted -- Sierran milkvetch, woollypod milkvetch
  Astragalus reventus var. conjunctus (S. Watson) M.E. Jones -- not accepted
  Astragalus robbinsii var. occidentalis S. Watson -- accepted -- Lamoille Canyon milkvetch, Robbins milk-vetch, western milkvetch
  Astragalus sesquiflorus S. Watson -- accepted -- sandstone milkvetch
  Astragalus tegetarius S. Watson -- not accepted
  Astragalus terminalis S. Watson -- accepted -- railhead milkvetch
  Astragalus thompsonae S. Watson -- not accepted
  Astragalus thompsoniae S. Watson -- not accepted
  Astragalus trichopodus ssp. antisellii (A. Gray ex W.H. Brewer & S. Watson) Thorne -- not accepted
  Astragalus trichopodus var. antisellii (A. Gray ex W.H. Brewer & S. Watson) Jeps. -- accepted -- Antisell's milkvetch, Santa Barbara milkvetch
  Astragalus troglodytus S. Watson -- accepted -- cliff-dweller's milkvetch, creeping milkvetch
  Astragalus vaseyi S. Watson -- not accepted
  Astragalus vaseyi var. vaseyi S. Watson -- not accepted
  Astragalus webberi A. Gray ex W.H. Brewer & S. Watson -- accepted -- Webber's milk-vetch
  Astragalus wingatanus S. Watson -- accepted -- Fort Wingate milkvetch
  Atamosco treatiae (S. Watson) Greene -- not accepted
  Athysanus pusillus var. glabrior S. Watson -- not accepted
  Atriplex acanthocarpa (Torr.) S. Watson -- accepted -- tubercled saltbush
  Atriplex acanthocarpa ssp. acanthocarpa (Torr.) S. Watson -- not accepted -- tubercled saltbush
  Atriplex acanthocarpa var. acanthocarpa (Torr.) S. Watson -- accepted -- tubercled saltbush
  Atriplex alaskensis S. Watson -- not accepted -- Alaska orache
  Atriplex argentea ssp. expansa (S. Watson) H.M. Hall & Clem. -- not accepted -- silverscale, silverscale saltbush
  Atriplex argentea var. expansa (S. Watson) S.L. Welsh & Reveal -- accepted -- silverscale saltbush
  Atriplex breweri S. Watson -- not accepted
  Atriplex canescens ssp. linearis (S. Watson) H.M. Hall & Clem. -- not accepted
  Atriplex canescens var. angustifolia (Torr.) S. Watson -- not accepted -- fourwing saltbush
  Atriplex canescens var. linearis (S. Watson) Munz -- not accepted -- thinleaf fourwing saltbush
  Atriplex confertifolia (Torr. & Frém.) S. Watson -- accepted -- shadscale, shadscale saltbush, spiny saltbush
  Atriplex coronata S. Watson -- accepted -- crownscale
  Atriplex coronata var. coronata S. Watson -- accepted -- crownscale
  Atriplex corrugata S. Watson -- accepted -- mat saltbush
  Atriplex decumbens S. Watson -- not accepted
  Atriplex elegans ssp. fasciculata (S. Watson) H.M. Hall & Clem. -- not accepted
  Atriplex elegans var. fasciculata (S. Watson) M.E. Jones -- accepted -- wheelscale, wheelscale saltbush
  Atriplex expansa S. Watson -- not accepted
  Atriplex fasciculata S. Watson -- not accepted
  Atriplex gmelinii var. alaskensis (S. Watson) S.L. Welsh -- accepted -- Alaska orache
  Atriplex hymenelytra (Torr.) S. Watson -- accepted -- desert holly, desertholly, Yuma desert holly
  Atriplex lentiformis (Torr.) S. Watson -- accepted -- big saltbush, quailbush
  Atriplex lentiformis ssp. breweri (S. Watson) H.M. Hall & Clem. -- not accepted -- quailbush
  Atriplex lentiformis ssp. lentiformis (Torr.) S. Watson -- not accepted -- big saltbush
  Atriplex lentiformis ssp. torreyi (S. Watson) H.M. Hall & Clem. -- not accepted
  Atriplex lentiformis var. breweri (S. Watson) McMinn -- not accepted
  Atriplex lentiformis var. torreyi (S. Watson) McMinn -- not accepted
  Atriplex linearis S. Watson -- accepted -- thinleaf fourwing saltbush
  Atriplex nuttallii S. Watson -- not accepted -- Nuttall's saltbush
  Atriplex nuttallii auct. non S. Watson -- not accepted -- Nuttall's saltbush
  Atriplex parishii S. Watson -- accepted -- Parish's saltbush, Parrish's brittlescale
  Atriplex parishii var. parishii S. Watson -- accepted -- Parish's saltbush
  Atriplex parryi S. Watson -- accepted -- Parry's saltbush
  Atriplex patula var. alaskensis (S. Watson) S.L. Welsh -- not accepted
  Atriplex patula var. subspicata (Nutt.) S. Watson -- not accepted
  Atriplex phyllostegia (Torr. ex S. Watson) S. Watson -- accepted -- arrow saltbush, arrow saltweed, leafcover saltweed
  Atriplex polycarpa (Torr.) S. Watson -- accepted -- cattle saltbush, desert saltbush
  Atriplex powellii S. Watson -- accepted -- Powell's orache, Powell's saltbush, Powell's saltweed
  Atriplex powellii var. powellii S. Watson -- accepted -- Powell's saltweed
  Atriplex pusilla (Torr. ex S. Watson) S. Watson -- accepted -- smallscale, smooth saltbush
  Atriplex saccaria S. Watson -- accepted -- sack saltbush, sack saltweed, stalked orache
  Atriplex saccaria var. saccaria S. Watson -- accepted -- stalked saltbush
  Atriplex texana S. Watson -- not accepted -- Texas saltbush
  Atriplex torreyi (S. Watson) S. Watson -- accepted -- Torrey saltbush, Torrey's quailbush, Torrey's saltbush
  Atriplex torreyi var. torreyi (S. Watson) S. Watson -- accepted -- Torrey's saltbush
  Atriplex truncata (Torr. ex S. Watson) A. Gray -- accepted -- wedgescale saltbush
  Atriplex wolfii S. Watson -- accepted -- Wolf's saltweed
  Atriplex wolfii var. wolfii S. Watson -- accepted -- Wolf's saltweed
  Atriplex wrightii S. Watson -- accepted -- Wright's saltbush
  Ayenia filiformis S. Watson -- accepted -- Trans-Pecos ayenia
  Ayenia glabra S. Watson -- accepted -- smooth ayenia
  Ayenia jaliscana S. Watson -- accepted
  Bahia schaffneri S. Watson -- accepted -- Schaffner's bahia
  Bahiopsis reticulata (S. Watson) E.E. Schill. & Panero -- accepted -- netvein goldeneye
  Bassia americana (S. Watson) A.J. Scott -- not accepted -- green molly
  Bassia californica (S. Watson) A.J. Scott -- not accepted -- rusty molly
  Bauhinia lunarioides A. Gray ex S. Watson -- accepted -- Texasplume
  Bernardia myricifolia (Scheele) S. Watson -- accepted -- mouse's eye, southwest bernardia
  Betula papyrifera var. minor (Tuck.) S. Watson & J.M. Coult. -- not accepted
  Bidens connata var. pinnata S. Watson -- not accepted
  Bifora americana Benth. & Hook. f. ex S. Watson -- accepted -- prairie bishop
  Blepharidachne bigelovii (S. Watson) Hack. -- accepted -- Bigelow desertgrass, Bigelow's desertgrass
  Blepharidachne kingii (S. Watson) Hack. -- accepted -- King's desertgrass, King's eyelashgrass
  Bloomeria clevelandii S. Watson -- accepted -- San Diego goldenstar
  Boechera beckwithii (S. Watson) Dorn -- not accepted -- silver rockcress
  Boechera breweri (S. Watson) Al-Shehbaz -- accepted -- Brewer's rockcress
  Boechera breweri ssp. breweri (S. Watson) Al-Shehbaz -- accepted -- Brewer's rockcress
  Boechera cusickii (S. Watson) Al-Shehbaz -- accepted -- Cusick's rockcress
  Boechera fendleri (S. Watson) W.A. Weber -- accepted -- Fendler's rockcress
  Boechera howellii (S. Watson) Windham & Al-Shehbaz -- accepted -- pioneer rockcress
  Boechera lemmonii (S. Watson) W.A. Weber -- accepted -- Lemmon's rockcress
  Boechera lyallii (S. Watson) Dorn -- accepted -- Lyall's rockcress
  Boechera macounii (S. Watson) Windham & Al-Shehbaz -- accepted -- Macoun's rockcress
  Boechera microphylla var. macounii (S. Watson) Rollins -- not accepted
  Boechera parishii (S. Watson) Al-Shehbaz -- accepted -- dwarf rockcress
  Boechera perennans (S. Watson) W.A. Weber -- accepted -- perennial rockcress
  Boechera pulchra (M.E. Jones ex S. Watson) W.A. Weber -- accepted -- beautiful rockcress
  Boechera repanda (S. Watson) Al-Shehbaz -- accepted -- Yosemite rockcress
  Boechera sparsiflora var. subvillosa (S. Watson) Dorn -- not accepted
  Boechera subpinnatifida (S. Watson) Al-Shehbaz -- accepted -- Klamath rockcress
  Boechera suffrutescens (S. Watson) Dorn -- accepted -- woody rockcress
  Boerhavia coulteri (Hook. f.) S. Watson -- accepted -- Coulter's spiderling
  Boerhavia coulteri var. coulteri (Hook. f.) S. Watson -- accepted -- Coulter's spiderling
  Boerhavia coulteri var. palmeri (S. Watson) Spellenb. -- accepted -- Coulter's spiderling
  Boerhavia pterocarpa S. Watson -- accepted -- Apache Pass spiderling
  Boerhavia torreyana (S. Watson) Standl. -- accepted -- creeping spiderling
  Boerhavia triquetra S. Watson -- accepted -- slender spiderling
  Boerhavia triquetra var. triquetra S. Watson -- accepted -- slender spiderling
  Boisduvalia densiflora (Lindl.) S. Watson -- not accepted
  Bolandra oregana S. Watson -- accepted -- northern false coolwort
  Bouteloua burkii Scribn. ex S. Watson -- not accepted
  Bouteloua chondrosioides (Kunth) Benth. ex S. Watson -- accepted -- sprucetop grama
  Bouteloua foenea (Torr.) Torr. ex S. Watson -- not accepted
  Bouteloua havardii Vasey ex S. Watson -- not accepted
  Bouteloua pilosa (Hook. f.) Benth. ex S. Watson -- not accepted
  Bouteloua polystachya S. Watson -- not accepted
  Bouteloua polystachya var. vestita S. Watson -- not accepted
  Bouteloua racemosa var. aristosa (A. Gray) S. Watson & J.M. Coult. -- not accepted
  Bouteloua texana S. Watson -- not accepted
  Bouteloua trifida var. burkii (Scribn. ex S. Watson) Vasey ex L.H. Dewey -- not accepted -- red grama
  Bouteloua vestita (S. Watson) Scribn. ex L.H. Dewey -- not accepted
  Brandegea bigelovii (S. Watson) Cogn. -- accepted -- desert starvine
  Brandegea palmeri (S. Watson) Rose -- not accepted
  Brandegea parviflora (S. Watson) Rose -- not accepted
  Braya alpina var. americana (Hook.) S. Watson -- not accepted
  Braya alpina var. glabella (Richardson) S. Watson -- not accepted
  Brickellia longifolia S. Watson -- accepted -- long leaf brickellbush, longleaf brickellbush
  Brickellia longifolia var. longifolia S. Watson -- accepted -- longleaf brickellbush
  Brizopyrum spicatum var. strictum (Torr.) A. Gray ex S. Watson -- not accepted
  Brodiaea bridgesii S. Watson -- not accepted
  Brodiaea crocea (Alph. Wood) S. Watson -- not accepted
  Brodiaea douglasii S. Watson -- not accepted
  Brodiaea douglasii var. howellii (S. Watson) M. Peck -- not accepted
  Brodiaea filifolia S. Watson -- accepted -- thread-leaved brodiaea, threadleaf brodiaea
  Brodiaea gracilis S. Watson -- not accepted
  Brodiaea hendersonii (Greene) S. Watson -- not accepted
  Brodiaea howellii S. Watson -- not accepted
  Brodiaea laxa (Benth.) S. Watson -- not accepted
  Brodiaea lemmoniae S. Watson -- not accepted
  Brodiaea minor (Benth.) S. Watson -- accepted -- vernalpool brodiaea
  Brodiaea palmeri S. Watson -- not accepted
  Brodiaea peduncularis (Lindl.) S. Watson -- not accepted
  Brodiaea stellaris S. Watson -- accepted -- starflower brodiaea
  Brongniartia minutifolia S. Watson -- accepted -- little leaf Brongniartia, littleleaf greentwig
  Caiandra schottii Torr. ex S. Watson -- not accepted
  Calandrinia ambigua (S. Watson) Howell -- not accepted
  Calandrinia breweri S. Watson -- accepted -- Brewer's redmaids
  Calandrinia cotyledon S. Watson -- not accepted
  Calandrinia howellii S. Watson -- not accepted
  Calandrinia oppositifolia S. Watson -- not accepted
  Calathea crotalifera S. Watson -- accepted -- rattlesnake plant
  Calia arizonica (S. Watson) Yakovlev -- not accepted
  Calliandra coulteri S. Watson -- not accepted -- Coulter's stickpea
  Calliandra schottii Torr. ex S. Watson -- not accepted -- Schott false mesquite, Schott's stickpea
  Callitriche sepulta S. Watson -- not accepted
  Callitropsis guadalupensis (S. Watson) D.P. Little -- accepted -- Guadeloupe cypress
  Calochortus aureus S. Watson -- accepted -- golden mariposa lily
  Calochortus caeruleus (Kellogg) S. Watson -- not accepted -- beavertail grass
  Calochortus catalinae S. Watson -- accepted -- Santa Catalina mariposa lily
  Calochortus clavatus S. Watson -- accepted -- clubhair mariposa lily
  Calochortus clavatus var. clavatus S. Watson -- accepted -- clubhair mariposa lily
  Calochortus coeruleus (Kellogg) S. Watson -- accepted -- beavertail grass
  Calochortus coeruleus var. coeruleus (Kellogg) S. Watson -- not accepted -- beavertail grass
  Calochortus eurycarpus S. Watson -- accepted -- bigpod mariposa lily, white mariposa lily
  Calochortus flexuosus S. Watson -- accepted -- straggling mariposa lily, weakstem mariposa lily, winding mariposa lily
  Calochortus greenei S. Watson -- accepted -- Greene's mariposa lily
  Calochortus gunnisonii S. Watson -- accepted -- Gunnison mariposa lily, Gunnison's mariposa lily
  Calochortus gunnisonii var. gunnisonii S. Watson -- accepted -- Gunnison mariposa lily, Gunnison's mariposa lily
  Calochortus howellii S. Watson -- accepted -- Howell's mariposa lily
  Calochortus longebarbatus S. Watson -- accepted -- longbeard mariposa lily
  Calochortus longebarbatus var. longebarbatus S. Watson -- accepted -- long-haired star-tulip, longbeard mariposa lily
  Calochortus luteus var. citrinus (Baker) S. Watson -- not accepted
  Calochortus luteus var. oculatus S. Watson -- not accepted
  Calochortus nudus S. Watson -- accepted -- naked mariposa lily
  Calochortus nuttallii var. aureus (S. Watson) Ownbey -- not accepted
  Calochortus palmeri S. Watson -- accepted -- Palmer's mariposa lily
  Calochortus palmeri var. palmeri S. Watson -- accepted -- Palmer's mariposa lily
  Calochortus venustus var. purpurascens S. Watson -- not accepted
  Calyptridium quadripetalum S. Watson -- not accepted
  Calyptridium roseum S. Watson -- not accepted
  Calystegia longipes (S. Watson) Brummitt -- accepted -- Paiute false bindweed, plateau morningglory
  Camassia cusickii S. Watson -- accepted -- Cusick's camas
  Camassia howellii S. Watson -- accepted -- Howell's camas
  Camassia leichtlinii (Baker) S. Watson -- accepted -- camas, great camas, large camas
  Camassia leichtlinii ssp. leichtlinii (Baker) S. Watson -- accepted -- large camas, Leichtlin camassia
  Camissonia boothii var. villosa (S. Watson) Cronquist -- not accepted
  Camissonia cheiranthifolia ssp. suffruticosa (S. Watson) P.H. Raven -- not accepted -- beach suncup
  Camissonia claviformis var. purpurascens (S. Watson) Cronquist -- not accepted
  Camissonia guadalupensis (S. Watson) P.H. Raven -- not accepted -- Guadalupe suncup
  Camissonia guadalupensis (S. Watson) P.H. Raven -- not accepted
  Camissonia heterochroma (S. Watson) P.H. Raven -- not accepted -- Shockley's evening primrose, Shockley's evening-primrose, Shockley's suncup
  Camissonia multijuga (S. Watson) P.H. Raven -- not accepted -- frost-stem suncup, froststem suncup
  Camissonia palmeri (S. Watson) P.H. Raven -- not accepted -- Palmer's evening primrose, Palmer's evening-primrose, Palmer's suncup, sagebrush suncup
  Camissonia parryi (S. Watson) P.H. Raven -- not accepted -- Parry's suncup, red-clay suncup, redclay suncup
  Camissonia pterosperma (S. Watson) P.H. Raven -- not accepted -- wing-fruit suncup, wingfruit suncup, wingseed suncup
  Camissonia pubens (S. Watson) P.H. Raven -- accepted -- hairy suncup
  Camissonia refracta (S. Watson) P.H. Raven -- not accepted -- narrow-leaf suncup, narrowleaf suncup
  Camissoniopsis cheiranthifolia ssp. suffruticosa (S. Watson) W.L. Wagner & Hoch -- accepted -- beach suncup
  Camissoniopsis guadalupensis (S. Watson) W.L. Wagner & Hoch -- accepted -- Guadalupe suncup
  Campanula floridana S. Watson ex A. Gray -- accepted -- Florida bellflower
  Canbya aurea S. Watson -- accepted -- golden pygmypoppy, yellow canbya
  Cardamine breweri S. Watson -- accepted -- Brewer bittercress, Brewer's bittercress
  Cardamine breweri var. breweri S. Watson -- not accepted -- Brewer's bittercress
  Cardamine californica var. pachystigma (S. Watson) O.E. Schulz -- not accepted
  Cardamine cordifolia var. lyallii (S. Watson) A. Nelson & J.F. Macbr. -- not accepted -- heartleaf bittercress, Lyall's bittercress
  Cardamine gambelii S. Watson -- not accepted
  Cardamine gambellii S. Watson -- not accepted
  Cardamine lyallii S. Watson -- not accepted
  Cardamine occidentalis (S. Watson) Howell -- accepted -- big western bittercress
  Cardamine pachystigma (S. Watson) Rollins -- accepted -- serpentine bittercress
  Cardamine pachystigma var. pachystigma (S. Watson) Rollins -- not accepted -- serpentine bittercress
  Cardamine pratensis var. occidentalis S. Watson -- not accepted
  Cardiospermum dissectum (S. Watson) Radlk. -- accepted -- Chihuahuan balloonvine
  Carsonia sparsifolia (S. Watson) Greene -- accepted -- fewleaf spiderflower
  Cassia armata S. Watson -- not accepted
  Castilleja exserta ssp. latifolia (S. Watson) T.I. Chuang & Heckard -- accepted -- wideleaf Indian paintbrush
  Castilleja flava S. Watson -- accepted -- yellow Indian paintbrush, yellow paintbrush
  Castilleja flava var. flava S. Watson -- accepted -- yellow Indian paintbrush
  Castilleja pilosa (S. Watson) Rydb. -- accepted -- hairy paintbrush, parrothead Indian paintbrush
  Castilleja pilosa var. pilosa (S. Watson) Rydb. -- accepted -- parrothead Indian paintbrush
  Cathartolinum kingii (S. Watson) Small -- not accepted
  Caulanthus S. Watson -- accepted -- wild cabbage
  Caulanthus amplexicaulis S. Watson -- accepted -- claspingleaf wild cabbage
  Caulanthus amplexicaulis var. amplexicaulis S. Watson -- not accepted -- claspingleaf wild cabbage
  Caulanthus californicus (S. Watson) Payson -- accepted -- California jewelflower, St. Francis cabbage
  Caulanthus cooperi (S. Watson) Payson -- accepted -- Cooper's wild cabbage, Cooper's wildcabbage
  Caulanthus coulteri S. Watson -- accepted -- Coulter's wild cabbage
  Caulanthus coulteri var. coulteri S. Watson -- not accepted -- Coulter's wild cabbage
  Caulanthus coulteri var. lemmonii (S. Watson) Munz -- not accepted
  Caulanthus crassicaulis (Torr.) S. Watson -- accepted -- thick-stem wild cabbage, thickstem wild cabbage, thickstem wildcabbage
  Caulanthus crassicaulis var. crassicaulis (Torr.) S. Watson -- not accepted -- thick-stem wild cabbage, thickstem wild cabbage, thickstem wildcabbage
  Caulanthus glaucus S. Watson -- accepted -- bigleaf wildcabbage, glaucous wild cabbage
  Caulanthus inflatus S. Watson -- accepted -- desert candle
  Caulanthus lemmonii S. Watson -- accepted -- Lemmon's wild cabbage
  Caulanthus pilosus S. Watson -- accepted -- hairy wild cabbage, hairy wildcabbage
  Ceanothus decumbens S. Watson -- not accepted
  Ceanothus herbaceus var. pubescens (Torr. & A. Gray ex S. Watson) Shinners -- not accepted
  Ceanothus ovatus var. pubescens Torr. & A. Gray ex S. Watson -- not accepted
  Ceanothus parvifolius (S. Watson) Trel. -- accepted -- littleleaf ceanothus
  Ceanothus pubescens (Torr. & A. Gray ex S. Watson) Rydb. ex Small -- not accepted
  Ceiba acuminata (S. Watson) Rose -- not accepted -- pochote
  Celosia palmeri S. Watson -- accepted -- Palmer's cock's comb
  Celtis brevipes S. Watson -- not accepted
  Celtis laevigata var. brevipes (S. Watson) Sarg. -- not accepted -- sugar hackberry, sugarberry
  Centaurium nuttallii (S. Watson) A. Heller -- not accepted
  Cerastium sericeum S. Watson -- not accepted
  Cercis canadensis ssp. texensis (S. Watson) E. Murray -- not accepted
  Cercis canadensis var. texensis (S. Watson) M. Hopkins -- accepted -- California redbud, Texas redbud
  Cercocarpus intricatus S. Watson -- not accepted -- littleleaf mountain-mahogany
  Cercocarpus intricatus var. intricatus S. Watson -- not accepted -- littleleaf mountain-mahogany
  Cercocarpus ledifolius var. intricatus (S. Watson) M.E. Jones -- accepted -- littleleaf mountain-mahogany
  Cercocarpus montanus var. glaber (S. Watson) F.L. Martin -- not accepted -- birchleaf mountain-mahogany
  Cercocarpus montanus var. paucidentatus (S. Watson) F.L. Martin -- not accepted -- hairy mountain-mahogany
  Cercocarpus parvifolius var. glaber S. Watson -- not accepted
  Cercocarpus parvifolius var. paucidentatus S. Watson -- not accepted
  Chaerophyllum dasycarpum (Hook. ex S. Watson) Nutt. ex Small -- not accepted
  Chaerophyllum tainturieri var. dasycarpum Hook. ex S. Watson -- accepted -- hairyfruit chervil
  Chaetadelpha A. Gray ex S. Watson -- accepted -- skeletonweed
  Chaetadelpha wheeleri A. Gray ex S. Watson -- accepted -- Wheeler's chaetadelpha, Wheeler's skeletonweed
  Chaetadelphia A. Gray ex S. Watson -- not accepted
  Chaetadelphia wheeleri A. Gray ex S. Watson -- not accepted
  Chamaebatiaria (Porter ex W.H. Brewer & S. Watson) Maxim. -- accepted -- desert sweet, fernbush
  Chamaesyce gracillima (S. Watson) Millsp. -- not accepted -- Mexican sandmat
  Chamaesyce hirtula (Engelm. ex S. Watson) Millsp. -- not accepted
  Chamaesyce intermixta (S. Watson) Millsp. -- not accepted
  Chamaesyce lineata (S. Watson) Millsp. -- not accepted
  Chamaesyce longeramosa (S. Watson) Millsp. -- not accepted
  Chamaesyce ocellata ssp. rattanii (S. Watson) Koutnik -- not accepted -- Rattan's sandmat
  Chamaesyce petrina (S. Watson) Millsp. -- not accepted
  Chamaesyce platysperma (Engelm. ex S. Watson) Shinners -- not accepted -- flat-seed sandmat, flat-seeded spurge, flatseed sandmat
  Chamaesyce portulana (S. Watson) Millsp. -- not accepted
  Chamaesyce rattanii (S. Watson) Millsp. -- not accepted
  Chamaesyce serpyllifolia ssp. hirtella (Engelm. ex S. Watson) Koutnik -- not accepted -- thymeleaf sandmat
  Chamaesyce serpyllifolia var. hirtella (Engelm. ex S. Watson) L.C. Wheeler -- not accepted
  Chamaesyce tomentulosa (S. Watson) Millsp. -- not accepted
  Cheirinia inconspicua (S. Watson) Rydb. -- not accepted
  Chenopodium californicum (S. Watson) S. Watson -- accepted -- California goosefoot
  Chenopodium farinosum (S. Watson) Standl. -- not accepted
  Chenopodium fremontii S. Watson -- accepted -- Fremont's goosefoot
  Chenopodium fremontii var. fremontii S. Watson -- not accepted -- Fremont's goosefoot
  Chenopodium fremontii var. incanum S. Watson -- not accepted
  Chenopodium incanum (S. Watson) A. Heller -- accepted -- mealy goosefoot, nealy goosefoot
  Chenopodium incanum var. incanum (S. Watson) A. Heller -- accepted -- mealy goosefoot
  Chenopodium leptophyllum (Moq.) Nutt. ex S. Watson -- accepted -- narrowleaf goosefoot, narrowleaf lambsquarters, narrowleaved goosefoot, slimleaf goosefoot, slimleaf lambsquarters
  Chenopodium leptophyllum var. oblongifolium S. Watson -- not accepted
  Chenopodium leptophyllum var. subglabrum S. Watson -- not accepted
  Chenopodium macrospermum var. farinosum (S. Watson) J.T. Howell -- not accepted -- largeseed goosefoot
  Chenopodium oblongifolium (S. Watson) Rydb. -- not accepted
  Chenopodium olidum S. Watson -- not accepted
  Chenopodium pratericola var. oblongifolium (S. Watson) Wahl -- not accepted
  Chenopodium rubrum var. humile auct. non (Hook.) S. Watson -- not accepted
  Chenopodium rubrum var. humile (Hook.) S. Watson -- accepted -- marshland goosefoot
  Chenopodium subglabrum (S. Watson) A. Nelson -- accepted -- smooth goosefoot
  Chlorocrambe hastata (S. Watson) Rydb. -- accepted -- spearhead
  Chlorogalum parviflorum S. Watson -- accepted -- smallflower soap plant
  Chorizanthe breweri S. Watson -- accepted -- Brewer's spineflower, San Luis Obispo spineflower
  Chorizanthe cuspidata S. Watson -- accepted -- San Francisco spineflower
  Chorizanthe cuspidata var. cuspidata S. Watson -- accepted -- San Francisco Bay spineflower, San Francisco spineflower
  Chorizanthe fernandina S. Watson -- not accepted
  Chorizanthe leptoceras (A. Gray) S. Watson -- not accepted
  Chorizanthe palmeri S. Watson -- accepted -- Palmer's spineflower
  Chorizanthe parryi S. Watson -- accepted -- San Bernardino spineflower
  Chorizanthe parryi var. fernandina (S. Watson) Jeps. -- accepted -- San Fernando Valley spineflower
  Chorizanthe parryi var. parryi S. Watson -- accepted -- Parry's spineflower, San Bernardino spineflower
  Chorizanthe spinosa S. Watson -- accepted -- Mojave spineflower
  Chorizanthe thurberi (A. Gray ex Benth.) S. Watson -- not accepted
  Chorizanthe valida S. Watson -- accepted -- Sonoma spineflower
  Chorizanthe wheeleri S. Watson -- accepted -- Santa Barbara spineflower
  Chorizanthe xanti S. Watson -- accepted -- Riverside spineflower
  Chorizanthe xanti var. xanti S. Watson -- accepted -- Riverside spineflower
  Chylismia heterochroma (S. Watson) Small -- accepted -- Shockley's evening primrose
  Chylismia multijuga (S. Watson) Small -- accepted -- froststem suncup
  Chylismia parryi (S. Watson) Small -- accepted -- redclay suncup
  Chylismiella pterosperma (S. Watson) W.L. Wagner & Hoch -- accepted -- wingfruit suncup
  Cicuta bolanderi S. Watson -- not accepted -- Bolander water-hemlock
  Cicuta maculata var. bolanderi (S. Watson) G.A. Mulligan -- accepted -- Bolander cicuta, common water hemlock, poison parsnip, spotted cowbane, spotted parsley, spotted water hemlock, water hemlock
  Cimicifuga arizonica S. Watson -- not accepted -- Arizona bugbane
  Cimicifuga laciniata S. Watson -- not accepted -- Mt. Hood bugbane
  Cistanthe ambigua (S. Watson) Hershk. -- accepted -- desert pussypaws
  Cistanthe quadripetala (S. Watson) Hershk. -- accepted -- fourpetal pussypaws
  Cistanthe rosea (S. Watson) Hershk. -- accepted -- rosy pussypaws
  Cladium californicum (S. Watson) O'Neill -- accepted -- California sawgrass
  Cladium mariscus var. californicum S. Watson -- not accepted
  Claytonia caroliniana var. lanceolata (Pall. ex Pursh) S. Watson -- not accepted
  Claytonia cordifolia S. Watson -- accepted -- heartleaf springbeauty
  Claytonia howellii (S. Watson) Piper -- not accepted
  Claytonia megarhiza (A. Gray) Parry ex S. Watson -- accepted -- alpine springbeauty
  Claytonia megarhiza var. megarhiza (A. Gray) Parry ex S. Watson -- not accepted -- alpine springbeauty
  Claytonia nevadensis S. Watson -- accepted -- Sierra springbeauty
  Claytonia sibirica var. cordifolia (S. Watson) R.J. Davis -- not accepted
  Claytonia triphylla S. Watson -- not accepted
  Claytonia umbellata S. Watson -- accepted -- Great Basin springbeauty
  Clematis fremontii S. Watson -- accepted -- Fremont's leather flower
  Clematis ligusticifolia var. californica S. Watson -- not accepted -- California clematis
  Cleome sparsifolia S. Watson -- not accepted -- fewleaf cleome, fewleaf spiderflower
  Cleomella brevipes S. Watson -- accepted -- shortstalk cleomella, shortstalk stinkweed
  Cleomella grandiflora (S. Watson) Coville -- not accepted
  Cleomella plocasperma S. Watson -- accepted -- alkali cleomella, alkali stinkweed, twisted cleomella
  Coldenia mexicana S. Watson -- not accepted
  Coldenia mexicana var. tomentosa (S. Watson) I.M. Johnst. -- not accepted
  Collinsia torreyi var. wrightii (S. Watson) I.M. Johnst. -- accepted -- Wright's blue eyed Mary
  Collinsia wrightii S. Watson -- not accepted
  Collomia debilis (S. Watson) Greene -- accepted -- alpine collomia
  Collomia debilis var. debilis (S. Watson) Greene -- accepted -- alpine collomia
  Colubrina greggii S. Watson -- accepted -- Sierra nakedwood, Sierran nakedwood
  Colubrina greggii var. greggii S. Watson -- not accepted -- Gregg's nakedwood
  Conioselinum chinense var. pacificum (S. Watson) B. Boivin -- not accepted
  Conioselinum pacificum (S. Watson) J.M. Coult. & Rose -- not accepted
  Conopholis alpina var. mexicana (A. Gray ex S. Watson) R.R. Haynes -- accepted -- alpine squawroot, Mexican cancer-root, Mexican squawroot
  Conopholis mexicana A. Gray ex S. Watson -- not accepted
  Convolvulus longipes S. Watson -- not accepted
  Corallorhiza bigelovii S. Watson -- not accepted
  Corallorrhiza bigelovii S. Watson -- not accepted
  Cordylanthus kingii S. Watson -- accepted -- King's bird's-beak, King's bird'sbeak
  Cordylanthus kingii ssp. kingii S. Watson -- accepted -- King's bird's-beak, King's bird'sbeak
  Corydalis bidwelliae S. Watson -- not accepted
  Corydalis brandegeei S. Watson -- not accepted
  Corydalis caseana ssp. brandegeei (S. Watson) G.B. Ownbey -- accepted -- Brandegee's fumewort
  Corydalis caseana ssp. cusickii (S. Watson) G.B. Ownbey -- accepted -- Cusick's fumewort
  Corydalis caseana var. cusickii (S. Watson) C.L. Hitchc. -- not accepted
  Corydalis cusickii S. Watson -- not accepted
  Cotyledon oregonensis S. Watson -- not accepted
  Crassula connata var. subsimplex (S. Watson) Bywater & Wickens -- not accepted -- sand pygmyweed
  Crassula viridis (S. Watson) Bywater & Wickens -- accepted -- pricklyseed pygmyweed
  Creonana vestitia (S. Watson) Jeps. -- not accepted
  Crossosoma bigelovii S. Watson -- accepted -- Bigelow's crossosoma, ragged rockflower
  Crossosoma bigelovii var. bigelovii S. Watson -- not accepted -- ragged rockflower
  Croton californicus var. major S. Watson ex Engelm. -- not accepted
  Croton californicus var. tenuis (S. Watson) A.M. Ferguson -- not accepted -- California croton
  Croton calvescens S. Watson -- not accepted
  Croton elaeagnoides S. Watson -- not accepted
  Croton palmeri S. Watson -- accepted
  Croton pringlei S. Watson -- not accepted
  Croton tenuilobus S. Watson -- accepted
  Croton tenuis S. Watson -- not accepted
  Cryptantha fulvocanescens (S. Watson) Payson -- accepted -- tawny catseye, tawny cryptantha
  Cryptantha fulvocanescens var. fulvocanescens (S. Watson) Payson -- accepted -- tawny cryptantha
  Cryptantha racemosa (S. Watson) Greene -- accepted -- brushy cryptantha, bushy cryptantha, forget-me-not cryptantha
  Cucurbita californica Torr. ex S. Watson -- not accepted
  Cucurbita palmata S. Watson -- accepted -- coyote gourd, coyote melon
  Cupressus guadalupensis S. Watson -- not accepted -- ciprés brillante
  Cymopterus bipinnatus S. Watson -- not accepted
  Cymopterus globosus (S. Watson) S. Watson -- accepted -- globe springparsley, globose springparsley
  Cymopterus longipes S. Watson -- accepted -- longstalk springparsley
  Cymopterus newberryi (S. Watson) M.E. Jones -- accepted -- sweet-root spring parsley, sweetroot springparsley
  Cymopterus nivalis S. Watson -- accepted -- snowline springparsley
  Cymopterus purpureus S. Watson -- accepted -- purple spring parsley, purple springparsley
  Cynanchum palmeri (S. Watson) Shinners -- not accepted
  Cynanchum palmeri (S. Watson) S.F. Blake -- not accepted
  Cynomarathrum alpinum (S. Watson) J.M. Coult. & Rose -- not accepted
  Cypripedium fasciculatum Kellogg ex S. Watson -- accepted -- clustered lady's slipper, clustered ladyslipper
  Dalea amoena S. Watson -- not accepted
  Dalea californica S. Watson -- not accepted
  Dalea flavescens (S. Watson) S.L. Welsh -- accepted -- Canyonlands prairie clover, Canyonlands prairieclover
  Dalea fremontii var. johnsonii (S. Watson) Munz -- not accepted
  Dalea glaberrima S. Watson -- not accepted
  Dalea kingii S. Watson -- not accepted
  Dalea orcuttii S. Watson -- not accepted
  Dalea polydenia Torr. ex S. Watson -- not accepted
  Dalea polydenia var. subnuda S. Watson -- not accepted
  Dalea reverchonii (S. Watson) Shinners -- accepted -- Comanche Peak prairie clover, Comanche-peak prairie-clover
  Dalea sabinalis (S. Watson) Shinners -- accepted -- Sabinal prairie-clover
  Dalea scariosa S. Watson -- accepted -- Albuquerque prairie clover, Albuquerque prairieclover
  Dasylirion wheeleri S. Watson -- accepted -- common sotol, sotol, Sotol de desierto
  Delphinium elatum var. occidentale S. Watson -- not accepted
  Delphinium glaucum S. Watson -- accepted -- mountain larkspur, Sierra larkspur, tower larkspur
  Delphinium madrense S. Watson -- accepted -- Sierra Madre larkspur
  Delphinium nelsonii ssp. utahense (S. Watson) Ewan -- not accepted
  Delphinium occidentale ssp. occidentale (S. Watson) S. Watson -- not accepted -- duncecap larkspur
  Delphinium scopulorum ssp. occidentale (S. Watson) Abrams -- not accepted
  Delphinium scopulorum var. glaucum (S. Watson) A. Gray -- not accepted
  Delphinium X occidentale (S. Watson) S. Watson (pro. sp.) -- accepted -- duncecap larkspur, tall larkspur
  Dentaria californica var. pachystigma S. Watson -- not accepted
  Dentaria pachystigma (S. Watson) S. Watson -- not accepted
  Dermatophyllum arizonicum (S. Watson) Vincent -- accepted -- Arizona necklacepod, Arizona sophora, mescal bean, mescalbean
  Desmanthus bicornutus S. Watson -- accepted -- ruby bundleflower, two-horn bundleflower
  Desmanthus obtusus S. Watson -- accepted -- bluntpod bundleflower
  Desmodium arizonicum S. Watson -- accepted -- Arizona tick trefoil, Arizona ticktrefoil
  Desmodium scopulorum S. Watson -- accepted -- Sonoran tick trefoil, Sonoran ticktrefoil
  Dicentra pauciflora S. Watson -- accepted -- shorthorn steer's-head
  Disporum hookeri var. oreganum (S. Watson) Q. Jones -- not accepted -- Oregon drops of gold
  Disporum hookeri var. parvifolium (S. Watson) Britton -- not accepted -- drops of gold
  Disporum oreganum (S. Watson) W.T. Mill. -- not accepted
  Disporum parvifolium (S. Watson) Britton -- not accepted
  Disporum trachycarpum (S. Watson) Benth. & Hook. f. -- not accepted -- rough-fruit fairybells, roughfruit fairybells, wartberry fairybells
  Douglasia dentata S. Watson -- not accepted
  Douglasia nivalis var. dentata (S. Watson) A. Gray -- not accepted -- snow dwarf-primrose
  Draba aureola S. Watson -- accepted -- Mt. Lassen draba
  Draba breweri S. Watson -- accepted -- cushion draba
  Draba breweri var. breweri S. Watson -- not accepted -- cushion draba
  Draba corrugata S. Watson -- accepted -- Southern California draba
  Draba corrugata var. corrugata S. Watson -- not accepted -- Southern California draba
  Draba cuneifolia var. integrifolia S. Watson -- accepted -- wedgeleaf draba, wedgeleaf whitlowgrass
  Draba cuneifolia var. platycarpa (Torr. & A. Gray) S. Watson -- not accepted
  Draba howellii S. Watson -- accepted -- rosette draba
  Draba lemmonii S. Watson -- accepted -- granite draba, Lemmon's draba
  Draba lemmonii var. lemmonii S. Watson -- not accepted -- granite draba, Lemmon's draba
  Draba nivalis var. elongata S. Watson -- not accepted
  Draba oligosperma ssp. subsessilis (S. Watson) A.E. Murray -- not accepted
  Draba oligosperma var. subsessilis (S. Watson) O.E. Schulz -- not accepted
  Draba sonorae var. integrifolia (S. Watson) O.E. Schulz -- not accepted
  Draba subsessilis S. Watson -- not accepted
  Dryas octopetala var. drummondii (Richardson ex Hook.) S. Watson -- not accepted
  Drymaria fendleri S. Watson -- not accepted
  Drymaria viscosa S. Watson -- accepted -- sticky drymary
  Dudleya attenuata (S. Watson) Moran -- accepted -- Orcutt's dudleya, tapertip liveforever
  Dudleya nevadensis (S. Watson) Britton & Rose -- not accepted
  Dudleya palmeri (S. Watson) Britton & Rose -- accepted -- Palmer's liveforever
  Dudleya variegata (S. Watson) Moran -- accepted -- variegated dudleya, variegated liveforever
  Dudleya viscida (S. Watson) Moran -- accepted -- sticky liveforever, sticky-leaved liveforever
  Duravia bidwelliae (S. Watson) Greene -- not accepted
  Echinodorus berteroi var. lanceolatus (Engelm. ex S. Watson & J.M. Coult.) Fassett -- not accepted
  Echinodorus rostratus var. lanceolatus Engelm. ex S. Watson & J.M. Coult. -- not accepted
  Echinopepon wrightii (A. Gray) S. Watson -- accepted -- wild balsam apple, wild balsam-apple
  Elaterium bigelovii S. Watson -- not accepted
  Eleocharis cancellata S. Watson -- accepted -- Arizona spikerush
  Eleocharis rostellata var. occidentalis S. Watson -- not accepted
  Elmera racemosa (S. Watson) Rydb. -- accepted -- yellow coralbells
  Elmera racemosa var. racemosa (S. Watson) Rydb. -- not accepted -- yellow coralbells
  Elymus canadensis var. intermedius Vasey ex S. Watson & J.M. Coult. -- not accepted
  Elymus sibiricus var. americanus S. Watson & J.M. Coult. -- not accepted
  Elymus virginicus var. intermedius (Vasey ex S. Watson & J.M. Coult.) Bush -- accepted
  Enneapogon wrightii (S. Watson) Roshev. -- not accepted
  Enneapogon wrightii (S. Watson) C.E. Hubb. -- not accepted
  Epallageiton longipes (S. Watson) Koso-Pol. -- not accepted
  Epallageiton purpureum (S. Watson) Koso-Pol. -- not accepted
  Ephedra aspera Engelm. ex S. Watson -- accepted -- aspera Mormon tea, boundary ephedra, Mormon tea, rough jointfir
  Ephedra californica S. Watson -- accepted -- California jointfir, California Mormon tea
  Ephedra californica var. californica S. Watson -- not accepted -- California jointfir
  Ephedra nevadensis S. Watson -- accepted -- Nevada ephedra, Nevada jointfir, Nevada Mormon tea
  Ephedra nevadensis var. aspera (Engelm. ex S. Watson) L.D. Benson -- not accepted
  Ephedra nevadensis var. nevadensis S. Watson -- not accepted -- Nevada jointfir
  Ephedra pedunculata Engelm. ex S. Watson -- accepted -- vine ephedra, vine jointfir
  Ephedra torreyana S. Watson -- accepted -- Torrey's ephedra, Torrey's jointfir, Torrey's Mormon tea
  Ephedra torreyana var. torreyana S. Watson -- accepted -- Torrey's jointfir, Torrey's Mormon tea
  Ephedra trifurca Torr. ex S. Watson -- accepted -- longleaf ephedra, longleaf jointfir, longleaf Mormon tea
  Epilobium torreyi (S. Watson) Hoch & P.H. Raven -- accepted -- narrowleaf willowweed, Torrey's willowherb
  Eragrostis elliottii S. Watson -- accepted -- field lovegrass
  Eragrostis palmeri S. Watson -- accepted -- Rio Grande lovegrass
  Eremochloe bigelovii S. Watson -- not accepted
  Eremochloe kingii S. Watson -- not accepted
  Eremochloe thurberi S. Watson -- not accepted
  Eremogone aculeata (S. Watson) Ikonn. -- accepted -- prickly sandwort
  Eremogone congesta var. subcongesta (S. Watson) R.L. Hartm. & Rabeler -- accepted -- loosehead sandwort
  Eremogone kingii (S. Watson) Ikonn. -- accepted -- King's sandwort
  Eremogone kingii var. glabrescens (S. Watson) Dorn -- accepted -- King's sandwort
  Eremogone kingii var. kingii (S. Watson) Ikonn. -- accepted -- King's sandwort
  Eremogone macradenia (S. Watson) Ikonn. -- accepted -- Mojave sandwort
  Eremogone macradenia var. macradenia (S. Watson) Ikonn. -- accepted -- Mojave sandwort
  Eremothera refracta (S. Watson) W.L. Wagner & Hoch -- accepted -- narrowleaf suncup
  Ericameria cervina (S. Watson) Rydb. -- accepted -- deer goldenbush, deer heath-goldenrod, deer heathgoldenrod
  Erigeron sanctarum S. Watson -- accepted -- saints fleabane
  Eriogonella spinosa (S. Watson) Goodman -- not accepted
  Eriogonum alatum ssp. triste (S. Watson) S. Stokes -- not accepted
  Eriogonum allenii S. Watson -- accepted -- shale barren buckwheat, shalebarren buckwheat
  Eriogonum apiculatum S. Watson -- accepted -- San Jacinto buckwheat
  Eriogonum baileyi S. Watson -- accepted -- Bailey's buckwheat
  Eriogonum baileyi var. baileyi S. Watson -- accepted -- Bailey's buckwheat
  Eriogonum baileyi var. tomentosum S. Watson -- not accepted
  Eriogonum cithariforme S. Watson -- accepted -- Cithara buckwheat
  Eriogonum cithariforme var. cithariforme S. Watson -- accepted -- Cithara buckwheat
  Eriogonum corymbosum var. thompsoniae (S. Watson) S.L. Welsh -- not accepted
  Eriogonum deflexum ssp. insigne (S. Watson) S. Stokes -- not accepted
  Eriogonum deserticola S. Watson -- accepted -- Colorado Desert buckwheat, desert wild buckwheat
  Eriogonum esmeraldense S. Watson -- accepted -- Esmeralda buckwheat
  Eriogonum esmeraldense var. esmeraldense S. Watson -- accepted -- Esmeralda buckwheat
  Eriogonum foliosum S. Watson -- accepted -- Baja buckwheat
  Eriogonum giganteum S. Watson -- accepted -- St. Catherine's lace
  Eriogonum giganteum var. giganteum S. Watson -- accepted -- St. Catherine's lace
  Eriogonum gracile var. cithariforme (S. Watson) Munz -- not accepted
  Eriogonum gracilipes S. Watson -- accepted -- White Mountain buckwheat
  Eriogonum gracillimum S. Watson -- accepted -- rose and white buckwheat
  Eriogonum harvardii S. Watson -- not accepted
  Eriogonum havardii S. Watson -- accepted -- Havard's buckwheat
  Eriogonum heermannii ssp. sulcatum (S. Watson) S. Stokes -- not accepted
  Eriogonum heermannii var. sulcatum (S. Watson) Munz & Reveal -- accepted -- Heermann's buckwheat
  Eriogonum hirtiflorum A. Gray ex S. Watson -- accepted -- hairyflower buckwheat
  Eriogonum hookeri S. Watson -- accepted -- Hooker's buckwheat, Hooker's eriogonum, Hooker's wild buckwheat
  Eriogonum inerme (S. Watson) Jeps. -- accepted -- unarmed buckwheat
  Eriogonum inerme var. inerme (S. Watson) Jeps. -- accepted -- unarmed buckwheat
  Eriogonum insigne S. Watson -- not accepted -- exalted buckwheat, ladder buckwheat, ladder wild buckwheat
  Eriogonum jamesii var. flavescens S. Watson -- not accepted -- James' buckwheat
  Eriogonum jonesii S. Watson -- accepted -- Jones' buckwheat
  Eriogonum kennedyi Porter ex S. Watson -- accepted -- Kennedy's buckwheat
  Eriogonum kennedyi ssp. gracilipes (S. Watson) S. Stokes -- not accepted
  Eriogonum kennedyi var. kennedyi Porter ex S. Watson -- accepted -- Kennedy's buckwheat
  Eriogonum latifolium ssp. pauciflorum (S. Watson) S. Stokes -- not accepted
  Eriogonum lemmonii S. Watson -- accepted -- Lemmon's buckwheat, volcanic buckwheat
  Eriogonum mohavense S. Watson -- accepted -- Western Mojave buckwheat
  Eriogonum molestum S. Watson -- accepted -- pineland buckwheat
  Eriogonum nudum ssp. pauciflorum (S. Watson) Munz -- not accepted
  Eriogonum nudum var. oblongifolium S. Watson -- accepted -- naked buckwheat
  Eriogonum nudum var. pauciflorum S. Watson -- accepted -- naked buckwheat
  Eriogonum ochrocephalum S. Watson -- accepted -- ocherflower buckwheat, whitewoolly buckwheat
  Eriogonum ochrocephalum var. gracilipes (S. Watson) J.T. Howell -- not accepted
  Eriogonum ochrocephalum var. ochrocephalum S. Watson -- accepted -- whitewoolly buckwheat
  Eriogonum ordii S. Watson -- accepted -- Fort Mojave buckwheat
  Eriogonum parishii S. Watson -- accepted -- mountainmist
  Eriogonum pendulum S. Watson -- accepted -- Waldo buckwheat
  Eriogonum puberulum S. Watson -- not accepted -- puberulent buckwheat, Red Creek buckwheat
  Eriogonum saxatile S. Watson -- accepted -- hoary buckwheat, rock buckwheat
  Eriogonum shockleyi S. Watson -- accepted -- Shockley's buckwheat, Shockley's wild buckwheat
  Eriogonum shockleyi var. shockleyi S. Watson -- not accepted -- Shockley's buckwheat
  Eriogonum subreniforme S. Watson -- accepted -- kidney-shape wild buckwheat, kidneyshape buckwheat
  Eriogonum suffruticosum S. Watson -- accepted -- bushy buckwheat, bushy wild-buckwheat
  Eriogonum sulcatum S. Watson -- not accepted
  Eriogonum thompsonae var. thompsonae S. Watson -- not accepted -- Thompson wild-buckwheat
  Eriogonum thompsoniae S. Watson -- accepted -- Thompson's buckwheat, Thompson's wild buckwheat
  Eriogonum thompsoniae var. thompsoniae S. Watson -- accepted -- Thompson's buckwheat
  Eriogonum triste S. Watson -- not accepted
  Eriogonum ursinum S. Watson -- accepted -- Bear Valley buckwheat
  Eriogonum ursinum var. ursinum S. Watson -- accepted -- Bear Valley buckwheat
  Eriogonum vimineum var. baileyi (S. Watson) R.J. Davis -- not accepted
  Eriogonum wrightii ssp. subscaposum (S. Watson) S. Stokes -- not accepted
  Eriogonum wrightii var. subscaposum S. Watson -- accepted -- bastardsage
  Eriogynia caespitosa (Nutt.) S. Watson -- not accepted
  Eriogynia uniflora S. Watson -- not accepted
  Erocallis triphylla (S. Watson) Rydb. -- not accepted
  Eryngium armatum (S. Watson) J.M. Coult. & Rose -- accepted -- coastal eryngo
  Erysimum arenicola S. Watson -- accepted -- cascade wallflower, Sierra wallflower
  Erysimum arenicola var. arenicola S. Watson -- not accepted -- cascade wallflower
  Erysimum asperum var. perenne S. Watson ex Coville -- not accepted
  Erysimum capitatum ssp. perenne (S. Watson ex Coville) R.A. Price -- not accepted
  Erysimum capitatum var. perenne (S. Watson ex Coville) R.J. Davis -- not accepted -- sand dune wallflower
  Erysimum inconspicum (S. Watson) MacMill. -- not accepted
  Erysimum inconspicuum (S. Watson) MacMill. -- accepted -- shy wallflower, smallflower wallflower
  Erysimum inconspicuum var. inconspicuum (S. Watson) MacMill. -- not accepted -- shy wallflower
  Erysimum occidentale (S. Watson) B.L. Rob. -- accepted -- pale wallflower, western wallflower
  Erysimum perenne (S. Watson ex Coville) Abrams -- accepted -- sand dune wallflower
  Erythronium citrinum S. Watson -- accepted -- cream fawnlily
  Erythronium citrinum var. citrinum S. Watson -- not accepted -- cream fawnlily
  Erythronium hendersonii S. Watson -- accepted -- Henderson's fawnlily
  Erythronium howellii S. Watson -- not accepted -- Howell's fawnlily
  Erythronium montanum S. Watson -- accepted -- white avalanche-lily
  Erythronium parviflorum (S. Watson) Goodd. -- not accepted
  Erythronium purpurascens S. Watson -- accepted -- purple fawnlily
  Eschscholzia minutiflora S. Watson -- accepted -- pygmy goldenpoppy, pygmy poppy
  Eschscholzia minutiflora ssp. minutiflora S. Watson -- accepted -- pygmy poppy, smallflower goldenpoppy
  Eumecanthus digitatus (S. Watson) Millsp. -- not accepted
  Eumecanthus guadalajaranus (S. Watson) Millsp. -- not accepted
  Eumecanthus subpeltatus (S. Watson) Millsp. -- not accepted
  Eumecanthus subreniformis (S. Watson) Millsp. -- not accepted
  Eumecanthus tener (S. Watson) Millsp. -- not accepted
  Euphorbia biformis S. Watson -- not accepted
  Euphorbia capitellata var. laxiflora S. Watson -- not accepted
  Euphorbia digitata S. Watson -- not accepted
  Euphorbia exclusa S. Watson -- not accepted
  Euphorbia gracillima S. Watson -- accepted -- Mexican sandmat
  Euphorbia guadalajarana S. Watson -- accepted
  Euphorbia hexagonoides S. Watson -- accepted
  Euphorbia hirtula Engelm. ex S. Watson -- not accepted
  Euphorbia intermixta S. Watson -- not accepted
  Euphorbia lineata S. Watson -- accepted
  Euphorbia longicornuta S. Watson -- accepted
  Euphorbia longiramosa S. Watson -- not accepted
  Euphorbia misella S. Watson -- accepted
  Euphorbia ocellata ssp. rattanii (S. Watson) Oudejans -- accepted -- Rattan's sandmat
  Euphorbia ocellata var. rattanii (S. Watson) L.C. Wheeler -- not accepted
  Euphorbia ocymoidea var. subreniformis (S. Watson) McVaugh -- not accepted
  Euphorbia palmeri Engelm. ex S. Watson -- not accepted -- wood spurge, woodland spurge
  Euphorbia palmeri var. palmeri Engelm. ex S. Watson -- not accepted -- woodland spurge
  Euphorbia palmeri var. subpubens (Engelm. ex S. Watson) L.C. Wheeler -- not accepted -- woodland spurge
  Euphorbia pediculifera var. linearifolia S. Watson -- accepted
  Euphorbia petrina S. Watson -- accepted
  Euphorbia platysperma Engelm. ex S. Watson -- accepted -- dune spurge, flat-seeded spurge, flatseed sandmat
  Euphorbia plicata S. Watson -- not accepted
  Euphorbia plummerae S. Watson -- not accepted
  Euphorbia plummeriae S. Watson -- not accepted
  Euphorbia polycarpa var. intermixta (S. Watson) L.C. Wheeler -- not accepted
  Euphorbia polycarpa var. petrina (S. Watson) I.M. Johnst. -- not accepted
  Euphorbia polycarpa var. vestita S. Watson -- not accepted
  Euphorbia portulana S. Watson -- not accepted
  Euphorbia rattanii S. Watson -- not accepted
  Euphorbia retroscabra S. Watson -- not accepted
  Euphorbia serpyllifolia ssp. hirtella (Engelm. ex S. Watson) Oudejans -- not accepted
  Euphorbia serpyllifolia var. hirtella (Engelm. ex S. Watson) L.C. Wheeler -- accepted -- thymeleaf sandmat
  Euphorbia serpyllifolia var. hirtula (Engelm. ex S. Watson) L.C. Wheeler -- accepted -- Thymeleaf sandmat
  Euphorbia subpeltata S. Watson -- accepted
  Euphorbia subpubens Engelm. ex S. Watson -- not accepted
  Euphorbia subreniformis S. Watson -- accepted
  Euphorbia tenera S. Watson -- not accepted
  Euphorbia tomentulosa S. Watson -- accepted
  Euphorbia uniglandulosa S. Watson -- not accepted
  Eurystemon mexicanum (S. Watson) Alexander -- not accepted
  Eurystemon mexicanus (S. Watson) Alexander -- not accepted
  Eysenhardtia orthocarpa (A. Gray) S. Watson -- accepted -- Tahitian kidneywood
  Fatsia horrida (Sm.) Benth. & Hook. f. ex W.H. Brewer & S. Watson -- not accepted
  Fendlerella utahensis (S. Watson) A. Heller -- accepted -- Utah fendlerbush, Utah fendlerella, yerba desierto
  Fendlerella utahensis var. utahensis (S. Watson) A. Heller -- not accepted -- Utah fendlerbush
  Festuca kingii (S. Watson) Cassidy -- not accepted -- spike fescue
  Festuca kingii (S. Watson) Scribn. -- not accepted
  Festuca kingii var. kingii (S. Watson) Cassidy -- not accepted
  Festuca ovina ssp. brevifolia (S. Watson) Hack. -- not accepted
  Festuca ovina var. brevifolia S. Watson -- not accepted
  Festuca ovina var. brevifolia auct. non S. Watson -- not accepted
  Filipendula occidentalis (S. Watson) Howell -- accepted -- queen of the forest, queen-of-the-forest
  Fimbristylis thermalis S. Watson -- accepted -- hot springs fimbry, hotsprings fimbry
  Fragaria glauca (S. Watson) Rydb. -- not accepted
  Fragaria virginiana ssp. glauca (S. Watson) Staudt -- accepted -- blueleaf strawberry, Virginia strawberry
  Fragaria virginiana var. glauca S. Watson -- not accepted
  Frankenia palmeri S. Watson -- accepted -- Palmer's frankenia, Palmer's seaheath
  Frasera albomarginata S. Watson -- accepted -- desert elkweed, desert frasera
  Frasera albomarginata var. albomarginata S. Watson -- not accepted -- desert elkweed
  Fraxinus anomala Torr. ex S. Watson -- accepted -- singleleaf ash
  Fraxinus anomala var. amonala Torr. ex S. Watson -- not accepted
  Fraxinus anomala var. anomala Torr. ex S. Watson -- accepted -- singleleaf ash
  Fraxinus velutina var. coriacea (S. Watson) Rehder -- not accepted
  Fritillaria mutica var. gracilis (S. Watson) Jeps. -- not accepted
  Galium bifolium S. Watson -- accepted -- twin-leaf bedstraw, twinleaf bedstraw
  Galium uncinulatum var. obstipum (Schltdl.) S. Watson -- not accepted
  Garrya flavescens S. Watson -- accepted -- ashy silktassel, yellowleaf silktassel
  Garrya flavescens ssp. flavescens S. Watson -- not accepted -- ashy silktassel
  Gastrolychnis kingii (S. Watson) W.A. Weber -- not accepted
  Gentiana amarella var. stricta (Griseb.) S. Watson -- not accepted
  Geranium bicknellii var. longipes (S. Watson) Fernald -- not accepted -- northern cranesbill
  Geranium carolinianum var. longipes S. Watson -- not accepted
  Geranium wislizeni S. Watson -- accepted -- Huachuca geranium, Huachuca Mountain geranium
  Geranium wislizenii S. Watson -- not accepted
  Gilia latifolia S. Watson -- not accepted -- broad-leaf gily-flower, broadleaf gilia
  Gilia latifolia var. latifolia S. Watson -- not accepted -- broadleaf gilia
  Glyceria arundinacea ssp. grandis (S. Watson) Tzvelev -- not accepted
  Glyceria grandis S. Watson -- accepted -- American mannagrass, manna grass
  Glyceria grandis f. grandis S. Watson -- not accepted
  Glyceria grandis var. grandis S. Watson -- accepted -- American mannagrass
  Glyceria maxima ssp. grandis (S. Watson) Hultén -- not accepted
  Glyceria maxima var. grandis (S. Watson) Breitung -- not accepted
  Glycyrrhiza lepidota var. glutinosa (Nutt.) S. Watson -- not accepted
  Godetia biloba (Durand) S. Watson -- not accepted
  Godetia epilobioides (Nutt. ex Torr. & A. Gray) S. Watson -- not accepted
  Godetia hispidula S. Watson -- not accepted
  Godetia purpurea var. parviflora (S. Watson) C.L. Hitchc. -- not accepted
  Gormania debilis (S. Watson) Britton -- not accepted
  Greggia camporum var. linearifolia (S. Watson) M.E. Jones -- not accepted
  Habenaria leucostachys (Lindl.) S. Watson -- not accepted
  Habenaria sparsiflora S. Watson -- not accepted
  Habenaria unalascensis (Spreng.) S. Watson -- not accepted
  Halliophytum fasciculatum (S. Watson) I.M. Johnst. -- not accepted
  Halostachys occidentalis S. Watson -- not accepted
  Haplopappus cervinus S. Watson -- not accepted
  Haplopappus crevinus S. Watson -- not accepted
  Hartwrightia A. Gray ex S. Watson -- accepted -- hartwrightia
  Hartwrightia floridana A. Gray ex S. Watson -- accepted -- Florida hartwrightia
  Hasseanthus variegatus (S. Watson) Rose -- not accepted
  Hastingsia S. Watson -- accepted -- rushlily
  Hastingsia alba (Durand) S. Watson -- accepted -- white rushlily
  Hastingsia bracteosa S. Watson -- accepted -- largeflower rushlily
  Hastingsia bracteosa var. bracteosa S. Watson -- not accepted -- largeflower rushlily
  Havardia sonorae (S. Watson) Britton & Rose -- accepted
  Hebanthe palmeri S. Watson -- not accepted
  Hechtia texensis S. Watson -- accepted -- Guapilla de Texas, Texas false agave
  Hedyotis nigricans var. scabra (S. Watson) Fosberg -- not accepted
  Helenium amarum var. badium (A. Gray ex S. Watson) Waterf. -- accepted -- basin sneezeweed, yellowdicks
  Helenium badium (A. Gray ex S. Watson) Greene -- not accepted
  Helenium tenuifolium var. badium A. Gray ex S. Watson -- not accepted
  Helianthus canescens (A. Gray) S. Watson -- not accepted
  Helianthus mollis var. cordatus S. Watson -- not accepted
  Hermannia pauciflora S. Watson -- accepted -- hierba del soldado, Santa Catalina burstwort
  Hermidium alipes S. Watson -- not accepted
  Hesperochiron S. Watson -- accepted
  Hesperochiron californicus (Benth.) S. Watson -- accepted -- California hesperochiron
  Hesperochloa kingii (S. Watson) Rydb. -- not accepted
  Hesperochloa kingii var. kingii (S. Watson) Rydb. -- not accepted
  Hesperonia tenuiloba (S. Watson) Standl. -- not accepted
  Heteranthera mexicana S. Watson -- accepted -- Mexican mudplantain
  Heuchera cylindrica var. alpina S. Watson -- not accepted -- alpine alumroot
  Heuchera micrantha var. hartwegii (S. Watson ex Wheelock) Rosend. -- accepted -- Hartweg's alumroot
  Heuchera racemosa S. Watson -- not accepted
  Hexalectris spicata var. arizonica (S. Watson) Catling & V.S. Engel -- accepted -- spiked crested coralroot
  Hibiscus biseptus S. Watson -- accepted -- Arizona rose-mallow, Arizona rosemallow
  Hollisteria S. Watson -- accepted
  Hollisteria lanata S. Watson -- accepted -- false spikeflower
  Holodiscus discolor var. dumosus (S. Watson) Maxim. ex J.M. Coult. -- accepted -- rockspirea
  Hookera filifolia (S. Watson) Greene -- not accepted
  Hookera stellaris (S. Watson) Greene -- not accepted
  Hookeria filifolia (S. Watson) Greene -- not accepted
  Horkelia baileyi (S. Watson) Rydb. -- not accepted
  Horkelia bolanderi ssp. parryi (S. Watson) D.D. Keck -- not accepted
  Horkelia fusca ssp. tenella (S. Watson) D.D. Keck -- not accepted -- pinewoods horkelia
  Horkelia fusca var. tenella S. Watson -- accepted -- pinewoods horkelia
  Horkelia purpurascens S. Watson -- not accepted
  Horkelia sericata S. Watson -- accepted -- silky horkelia
  Horkeliella purpurascens (S. Watson) Rydb. -- accepted -- purple false horkelia
  Horsfordia alata (S. Watson) A. Gray -- accepted -- big feltplant, pink velvetmallow
  Horsfordia newberryi (S. Watson) A. Gray -- accepted -- Newberry's velvetmallow, yellow feltplant
  Horsfordia palmeri S. Watson -- not accepted
  Hosackia nevadensis (S. Watson) Parish -- not accepted
  Hosackia nivea (Greene) S. Watson -- not accepted
  Hulsea callicarpha (H.M. Hall) S. Watson ex Rydb. -- not accepted
  Hydrophyllum capitatum var. alpinum S. Watson -- accepted -- alpine waterleaf
  Hydrophyllum occidentale (S. Watson) A. Gray -- accepted -- squaw-lettuce, western waterleaf
  Hymenocallis humilis S. Watson -- not accepted
  Hymenocallis palmeri S. Watson -- accepted -- alligatorlily
  Hypericum microsepalum (Torr. & A. Gray) A. Gray ex S. Watson -- accepted -- flatwoods St. Johnswort
  Hypericum paucifolium S. Watson -- accepted
  Ilex verticillata var. padifolia (Willd.) Torr. & A. Gray ex S. Watson -- not accepted
  Ilex verticillata var. tenuifolia (Torr.) S. Watson -- not accepted
  Iresine palmeri (S. Watson) Standl. -- accepted -- Palmer's bloodleaf
  Iris bracteata S. Watson -- accepted -- Siskiyou iris
  Iris tenuis S. Watson -- accepted -- Clackamas iris
  Isoloma jaliscanum S. Watson -- not accepted
  Ivesia baileyi S. Watson -- accepted -- Bailey's ivesia
  Ivesia baileyi ssp. setosa (S. Watson) D.D. Keck -- not accepted
  Ivesia baileyi var. baileyi S. Watson -- accepted -- Bailey's ivesia
  Ivesia baileyi var. setosa S. Watson -- not accepted -- Bailey's ivesia
  Ivesia gordonii var. pygmea (A. Gray) S. Watson -- not accepted -- Gordon's ivesia
  Ivesia kingii S. Watson -- accepted -- Ash Meadows ivesia, King's ivesia, King's mousetail
  Ivesia kingii var. kingii S. Watson -- accepted -- alkali ivesia
  Ivesia lemmonii S. Watson -- not accepted
  Ivesia pinnatifida S. Watson -- not accepted
  Ivesia purpurascens (S. Watson) D.D. Keck -- not accepted
  Ivesia purpurascens ssp. purpurascens (S. Watson) D.D. Keck -- not accepted -- summit mousetail
  Ivesia setosa (S. Watson) Rydb. -- accepted
  Ivesia shockleyi S. Watson -- accepted -- Shockley's ivesia, sky mousetail
  Ivesia shockleyi var. shockleyi S. Watson -- accepted -- Shockley's ivesia, sky mousetail
  Ivesia utahensis S. Watson -- accepted -- Utah mousetail
  Jacquemontia palmeri S. Watson -- not accepted
  Johanneshowellia puberula (S. Watson) Reveal -- accepted -- Red Creek buckwheat
  Juglans californica S. Watson -- accepted -- California black walnut, Southern California walnut
  Juglans californica var. californica S. Watson -- not accepted -- California walnut, southern California black walnut
  Juncoides carolinae (S. Watson) Kuntze -- not accepted
  Juncus bufonius var. cogdonii (S. Watson) J.T. Howell -- not accepted
  Juncus bufonius var. congdonii (S. Watson) J.T. Howell -- not accepted
  Juncus nevadensis S. Watson -- accepted -- Nevada rush, Sierra rush
  Juncus nevadensis var. nevadensis S. Watson -- not accepted -- Nevada rush, Sierra rush
  Juncus oreganus S. Watson -- not accepted
  Justicia candicans var. subglabra (S. Watson) L.D. Benson -- not accepted
  Kallstroemia californica (S. Watson) Vail -- accepted -- California caltrop
  Kelseya uniflora (S. Watson) Rydb. -- accepted -- oneflower kelseya
  Kelseyi (S. Watson) Rydb. -- not accepted
  Kelseyi uniflora (S. Watson) Rydb. -- not accepted
  Kochia americana S. Watson -- accepted -- greenmolly, greenmolly kochia, greenmolly summercypress
  Kochia americana var. californica (S. Watson) M.E. Jones -- not accepted
  Kochia americana var. vestita S. Watson -- not accepted
  Kochia californica S. Watson -- accepted -- Mojave kochia, rusty molly
  Kochia vestita (S. Watson) Rydb. -- not accepted
  Krameria bicolor S. Watson -- accepted
  Krameria ramosissima (A. Gray) S. Watson -- accepted -- manystem ratany, trailing ratany
  Laothoe parviflora (S. Watson) Greene -- not accepted
  Laphamia megalocephala S. Watson -- not accepted
  Lappula echinata var. occidentalis (S. Watson) B. Boivin -- not accepted
  Lappula occidentalis (S. Watson) Greene -- accepted -- flat-spine sheepburr, flatspine stickseed, western sticktight
  Lappula occidentalis var. occidentalis (S. Watson) Greene -- accepted -- desert stickseed, flat-spine sheepburr, flatspine stickseed, western stickseed
  Lappula redowskii var. occidentalis (S. Watson) Rydb. -- not accepted
  Lathyrus bolanderi S. Watson -- not accepted
  Lathyrus cusickii S. Watson -- not accepted
  Lathyrus graminifolius (S. Watson) T.G. White -- accepted -- grassleaf pea, grassleaf peavine
  Lathyrus jepsonii ssp. californicus (S. Watson) C.L. Hitchc. -- not accepted -- California pea
  Lathyrus jepsonii var. californicus (S. Watson) Hoover -- accepted -- California pea
  Lathyrus nevadensis S. Watson -- accepted -- Sierra pea
  Lathyrus nevadensis ssp. cusickii (S. Watson) C.L. Hitchc. -- not accepted -- Sierra pea
  Lathyrus nevadensis ssp. lanceolatus var. nuttallii (S. Watson) C.L. Hitchc. -- not accepted -- Sierra pea
  Lathyrus nevadensis ssp. nevadensis S. Watson -- not accepted -- Sierra pea
  Lathyrus nevadensis var. cusickii (S. Watson) Broich -- accepted -- Sierra pea
  Lathyrus nevadensis var. nevadensis S. Watson -- accepted -- Sierra pea, wild pea
  Lathyrus nevadensis var. nuttallii (S. Watson) C.L. Hitchc. -- not accepted -- Sierra pea
  Lathyrus nuttallii S. Watson -- not accepted
  Lathyrus parviflorus S. Watson -- accepted
  Lathyrus vestitus ssp. bolanderi (S. Watson) C.L. Hitchc. -- not accepted -- Bolander's pea
  Lavatera occidentalis S. Watson -- not accepted
  Lavatera venosa S. Watson -- not accepted
  Lepidium campestre var. heterophyllum (S. Watson) C.L. Hitchc. -- not accepted
  Lepidium fremontii S. Watson -- accepted -- desert pepperweed
  Lepidium fremontii var. fremontii S. Watson -- not accepted -- desert pepperweed
  Lepidium integrifolium var. heterophyllum S. Watson -- not accepted -- thickleaf pepperweed
  Lepidium montanum var. alpinum S. Watson -- not accepted -- alpine pepperweed
  Lepidium montanum var. heterophyllum (S. Watson) C.L. Hitchc. -- not accepted
  Lepidium nanum S. Watson -- accepted -- dwarf pepperweed
  Lepidium strictum (S. Watson) Rattan -- accepted -- upright pepperweed
  Lepidospartum latisquamum S. Watson -- accepted -- Nevada broomsage
  Lespedeza intermedia (S. Watson) Britton -- not accepted
  Lesquerella S. Watson -- not accepted -- bladderpod, bladderpod species
  Lesquerella alpina (Nutt.) S. Watson -- not accepted -- alkaline bladderpod, alpine bladderpod
  Lesquerella alpina var. alpina (Nutt.) S. Watson -- not accepted -- alpine bladderpod
  Lesquerella angustifolia (Nutt. ex Torr. & A. Gray) S. Watson -- not accepted -- annual bladderpod, thread-leaved bladderpod, threadleaf bladderpod
  Lesquerella arctica (Wormsk. ex Hornem.) S. Watson -- not accepted -- arctic bladderpod
  Lesquerella arctica ssp. purshii (S. Watson) A.E. Porsild -- not accepted
  Lesquerella arctica var. purshii S. Watson -- not accepted
  Lesquerella argentea (Schauer) S. Watson -- not accepted
  Lesquerella argyraea (A. Gray) S. Watson -- not accepted -- bladderpod, silver bladderpod
  Lesquerella arizonica S. Watson -- not accepted -- Arizona bladderpod
  Lesquerella auriculata (Engelm. & A. Gray) S. Watson -- not accepted -- earleaf bladderpod
  Lesquerella berlandieri S. Watson -- not accepted
  Lesquerella cinerea S. Watson -- not accepted -- basin bladderpod
  Lesquerella densiflora (A. Gray) S. Watson -- not accepted -- denseflower bladderpod
  Lesquerella douglasii S. Watson -- not accepted -- Douglas' bladderpod
  Lesquerella engelmannii (A. Gray) S. Watson -- not accepted -- Engelmann's bladderpod
  Lesquerella fendleri (A. Gray) S. Watson -- not accepted -- Fendler bladderpod, Fendler's bladderpod
  Lesquerella globosa (Desv.) S. Watson -- not accepted -- globe bladderpod, Short's bladderpod
  Lesquerella gordonii (A. Gray) S. Watson -- not accepted -- Gordon's bladderpod
  Lesquerella gordonii var. gordonii (A. Gray) S. Watson -- not accepted -- Gordon's bladderpod
  Lesquerella gordonii var. sessilis S. Watson -- not accepted
  Lesquerella gracilis (Hook.) S. Watson -- not accepted -- lax bladderpod, spreading bladderpod
  Lesquerella gracilis ssp. gracilis (Hook.) S. Watson -- not accepted -- spreading bladderpod
  Lesquerella grandiflora (Hook.) S. Watson -- not accepted -- bigflower bladderpod
  Lesquerella intermedia (S. Watson) A. Heller -- not accepted -- mid bladderpod, Santa Fe bladderpod
  Lesquerella kingii S. Watson -- not accepted -- King bladderpod, King's bladderpod
  Lesquerella kingii ssp. kingii S. Watson -- not accepted -- King bladderpod, King's bladderpod
  Lesquerella kingii ssp. kingii var. kingii S. Watson -- not accepted -- King bladderpod, King's bladderpod
  Lesquerella kingii var. kingii S. Watson -- not accepted -- King bladderpod
  Lesquerella lasiocarpa (Hook. ex A. Gray) S. Watson -- not accepted -- roughpod bladderpod
  Lesquerella lasiocarpa ssp. berlandieri var. hispida (S. Watson) Rollins & E.A. Shaw -- not accepted -- hairy roughpod bladderpod
  Lesquerella lasiocarpa ssp. lasiocarpa (Hook. ex A. Gray) S. Watson -- not accepted -- roughpod bladderpod
  Lesquerella lasiocarpa var. hispida (S. Watson) Rollins & E.A. Shaw -- not accepted -- roughpod bladderpod
  Lesquerella lasiocarpa var. lasiocarpa (Hook. ex A. Gray) S. Watson -- not accepted -- roughpod bladderpod
  Lesquerella lescurii (A. Gray) S. Watson -- not accepted -- Lescur's bladderpod
  Lesquerella lindheimeri (A. Gray) S. Watson -- not accepted -- Lindheimer's bladderpod
  Lesquerella ludoviciana (Nutt.) S. Watson -- not accepted -- foothill bladderpod, Louisiana bladderpod, silver bladderpod
  Lesquerella ludoviciana var. arenosa (Richardson) S. Watson -- not accepted
  Lesquerella montana (A. Gray) S. Watson -- not accepted -- mountain bladderpod
  Lesquerella nuttallii (Torr. & A. Gray) S. Watson -- not accepted
  Lesquerella occidentalis S. Watson -- not accepted -- western bladderpod
  Lesquerella occidentalis ssp. occidentalis S. Watson -- not accepted -- western bladderpod
  Lesquerella pallida (Torr. & A. Gray) S. Watson -- not accepted -- white bladderpod
  Lesquerella palmeri S. Watson -- not accepted -- bladder pod
  Lesquerella purpurea (A. Gray) S. Watson -- not accepted -- purple bladderpod, rose bladderpod
  Lesquerella purpurea var. purpurea (A. Gray) S. Watson -- not accepted
  Lesquerella purshii (S. Watson) Fernald -- not accepted
  Lesquerella recurvata (Engelm. ex A. Gray) S. Watson -- not accepted -- gaslight bladderpod
  Lesquerella repanda (Nutt.) S. Watson -- not accepted
  Lesquerella sessilis (S. Watson) Small -- not accepted -- sessile bladderpod
  Lesquerella wardii S. Watson -- not accepted -- Ward's bladderpod
  Leucaena greggii S. Watson -- accepted
  Leucocraspedum albomarginatum (S. Watson) Rydb. -- not accepted
  Leucopoa kingii (S. Watson) W.A. Weber -- accepted -- spike fescue, spike-fescue
  Lewisia cottyedon (S. Watson) B. Rob. -- not accepted
  Lewisia cotyledon (S. Watson) B.L. Rob. -- accepted -- Siskiyou lewisia
  Lewisia cotyledon var. cotyledon (S. Watson) B.L. Rob. -- accepted -- Siskiyou lewisia
  Lewisia cotyledon var. howellii (S. Watson) Jeps. -- accepted -- Howell's lewisia
  Lewisia howellii (S. Watson) B.L. Rob. -- not accepted
  Lewisia oppositifolia (S. Watson) B.L. Rob. -- accepted -- oppositeleaf lewisia
  Lewisia triphylla (S. Watson) B.L. Rob. -- accepted -- threeleaf bitterroot, threeleaf lewisia
  Ligusticum filicinum S. Watson -- accepted -- fernleaf licorice-root, fernleaf licoriceroot
  Ligusticum filicinum var. tenuifolium (S. Watson) Mathias & Constance -- not accepted
  Ligusticum tenuifolium S. Watson -- accepted -- Idaho licorice-root
  Lilium bolanderi S. Watson -- accepted -- Bolander's lily
  Lilium grayi S. Watson -- accepted -- Gray's lily
  Lilium parryi S. Watson -- accepted -- lemon lily, Parry lily
  Lilium rubescens S. Watson -- accepted -- redwood lily
  Limnorchis sparsiflora (S. Watson) Rydb. -- not accepted
  Linum kingii S. Watson -- accepted -- King's flax
  Loeselia greggii S. Watson -- accepted -- Chisos Mountain false calico
  Lomatium bicolor (S. Watson) J.M. Coult. & Rose -- accepted -- Wasatch biscuitroot, Wasatch desert-parsley, Wasatch desertparsley
  Lomatium bicolor var. bicolor (S. Watson) J.M. Coult. & Rose -- accepted -- Wasatch desertparsley
  Lomatium circumdatum (S. Watson) J.M. Coult. & Rose -- not accepted
  Lomatium cous (S. Watson) J.M. Coult. & Rose -- accepted -- cous biscuitroot, Cous' biscuitroot, cous-root desert-parsley
  Lomatium cusickii (S. Watson) J.M. Coult. & Rose -- accepted -- Cusick's biscuitroot
  Lomatium geyeri (S. Watson) J.M. Coult. & Rose -- accepted -- Geyer's biscuitroot
  Lomatium graveolens (S. Watson) Dorn & R.L. Hartm. -- accepted -- king desertparsley, King's biscuitroot
  Lomatium graveolens var. alpinum (S. Watson) Dorn & R.L. Hartm. -- accepted -- alpine biscuitroot
  Lomatium graveolens var. graveolens (S. Watson) Dorn & R.L. Hartm. -- accepted -- king desertparsley
  Lomatium hallii (S. Watson) J.M. Coult. & Rose -- accepted -- Hall's biscuitroot
  Lomatium howellii (S. Watson) Jeps. -- accepted -- Howell's biscuitroot, Howell's lomatium
  Lomatium kingii (S. Watson) Cronquist -- not accepted
  Lomatium kingii var. alpinum (S. Watson) Cronquist -- not accepted
  Lomatium nevadense (S. Watson) J.M. Coult. & Rose -- accepted -- Nevada biscuitroot, Nevada desert-parsley
  Lomatium nevadense var. nevadense (S. Watson) J.M. Coult. & Rose -- accepted -- Nevada biscuitroot
  Lomatium nuttallii var. alpinum (S. Watson) Mathias -- not accepted
  Lomatium parryi (S. Watson) J.F. Macbr. -- accepted -- Parry's biscuitroot, Utah desert-parsley, Utah desertparsley
  Lomatium suksdorfii (S. Watson) J.M. Coult. & Rose -- accepted -- Suksdorf's desert-parsley, Suksdorf's desertparsley
  Lonicera utahensis S. Watson -- accepted -- Utah honeysuckle
  Lotus chihuahuanus (S. Watson) Greene -- accepted
  Lotus douglasii var. nevadensis (S. Watson) Ottley -- not accepted
  Lotus nevadensis (S. Watson) Greene -- not accepted -- Nevada bird's-foot trefoil, Nevada trefoil
  Lotus nevadensis var. nevadensis (S. Watson) Greene -- not accepted -- Nevada bird's-foot trefoil, Nevada trefoil
  Lotus nevandensis (S. Watson) Greene -- not accepted
  Luetkea caespitosa var. elatior (S. Watson) Britton -- not accepted
  Lupinus albifrons var. longifolius (S. Watson) Isely -- not accepted
  Lupinus andersonii S. Watson -- accepted -- Anderson's lupine
  Lupinus andersonii var. grayi S. Watson -- not accepted
  Lupinus arboreus var. fruticosus (Sims) S. Watson -- not accepted
  Lupinus arcticus S. Watson -- accepted -- arctic lupine
  Lupinus arcticus ssp. arcticus S. Watson -- accepted -- arctic lupine
  Lupinus argenteus var. argophyllus (A. Gray) S. Watson -- not accepted
  Lupinus argenteus var. decumbens (Torr.) S. Watson -- not accepted
  Lupinus argenteus var. heteranthus (S. Watson) Barneby -- not accepted
  Lupinus argenteus var. palmeri (S. Watson) Barneby -- not accepted
  Lupinus argenteus var. utahensis (S. Watson) Barneby -- not accepted
  Lupinus aridus var. cusickii (S. Watson) C.P. Sm. -- not accepted
  Lupinus aridus var. lobbii A. Gray ex S. Watson -- not accepted
  Lupinus aridus var. torreyi (A. Gray ex S. Watson) C.P. Sm. -- not accepted
  Lupinus aridus var. utahensis S. Watson -- not accepted
  Lupinus arizonicus (S. Watson) S. Watson -- accepted -- Arizona lupine
  Lupinus arizonicus ssp. arizonicus (S. Watson) S. Watson -- accepted -- Arizona lupine
  Lupinus arizonicus ssp. arizonicus var. arizonicus (S. Watson) S. Watson -- not accepted -- Arizona lupine
  Lupinus arizonicus var. arizonicus (S. Watson) S. Watson -- accepted -- Arizona lupine
  Lupinus barbiger S. Watson -- accepted -- bearded lupine
  Lupinus bicolor ssp. microphyllus (S. Watson) D.B. Dunn -- accepted -- miniature annual lupine, miniature lupine
  Lupinus bicolor ssp. umbellatus var. trifidus (S. Watson) C.P. Sm. -- not accepted -- miniature lupine
  Lupinus bicolor var. microphyllus (S. Watson) C.P. Sm. -- not accepted
  Lupinus bicolor var. trifidus (S. Watson) C.P. Sm. -- accepted -- miniature lupine
  Lupinus brevicaluis S. Watson -- not accepted
  Lupinus brevicaulis S. Watson -- accepted -- shortstem lupine
  Lupinus bridgesii (S. Watson) A. Heller -- not accepted
  Lupinus burkei S. Watson -- accepted -- largeleaf lupine
  Lupinus burkei ssp. burkei S. Watson -- accepted -- Burke's lupine, largeleaf lupine
  Lupinus caespitosus var. utahensis (S. Watson) B.J. Cox -- accepted -- Utah lupine
  Lupinus caudatus var. utahensis (S. Watson) S.L. Welsh -- not accepted
  Lupinus chamissonis var. longifolius S. Watson -- not accepted
  Lupinus chihuahuensis S. Watson -- accepted -- Chihuahuan lupine
  Lupinus concinnus ssp. orcuttii (S. Watson) D.B. Dunn -- accepted -- Orcutt lupine, Orcutt's lupine
  Lupinus concinnus var. arizonicus S. Watson -- not accepted
  Lupinus concinnus var. orcuttii (S. Watson) C.P. Sm. -- not accepted
  Lupinus cusickii S. Watson -- accepted -- Cusick's lupine
  Lupinus cusickii ssp. cusickii S. Watson -- accepted -- Cusick's lupine
  Lupinus formosus var. bridgesii (S. Watson) Greene -- not accepted
  Lupinus glabratus (S. Watson) Rydb. -- not accepted
  Lupinus grayi (S. Watson) S. Watson -- accepted -- Gray's lupine, Sierra lupine
  Lupinus havardii S. Watson -- accepted -- Big Bend bluebonnet, Chisos bluebonnet
  Lupinus holosericeus var. utahensis S. Watson -- not accepted
  Lupinus kingii S. Watson -- accepted -- King's lupine
  Lupinus kingii var. kingii S. Watson -- accepted -- King's lupine
  Lupinus lepidus ssp. cusickii (S. Watson) Detling -- not accepted
  Lupinus lepidus var. cusickii (S. Watson) C.L. Hitchc. -- not accepted
  Lupinus lepidus var. lobbii (A. Gray ex S. Watson) C.L. Hitchc. -- not accepted
  Lupinus lepidus var. torreyi (A. Gray ex S. Watson) Jeps. -- not accepted
  Lupinus lepidus var. utahensis (S. Watson) C.L. Hitchc. -- not accepted
  Lupinus lobbii (A. Gray ex S. Watson) A. Gray ex Greene -- not accepted
  Lupinus longifolius (S. Watson) Abrams -- accepted -- longleaf bush lupine
  Lupinus lyallii ssp. lyallii var. danaus (A. Gray) S. Watson -- not accepted -- dwarf mountain lupine, Lyall's lupine
  Lupinus lyallii var. danaus (A. Gray) S. Watson -- accepted -- dwarf mountain lupine
  Lupinus lyallii var. lobbii (A. Gray ex S. Watson) C.P. Sm. -- not accepted
  Lupinus meionanthus var. heteranthus S. Watson -- not accepted
  Lupinus micranthus var. bicolor (Lindl.) S. Watson -- not accepted
  Lupinus micranthus var. microphyllus S. Watson -- not accepted
  Lupinus micranthus var. trifidus S. Watson -- not accepted
  Lupinus nootkatensis var. unalaskensis S. Watson -- not accepted
  Lupinus nuttallii S. Watson -- not accepted
  Lupinus onustus S. Watson -- accepted -- Plumas lupine
  Lupinus orcuttii S. Watson -- not accepted
  Lupinus ornatus var. glabratus S. Watson -- not accepted
  Lupinus palmeri S. Watson -- accepted -- bluebonnet lupine, Palmer's lupine
  Lupinus perennis ssp. perennis var. occidentalis S. Watson -- not accepted -- sundial lupine
  Lupinus perennis var. occidentalis S. Watson -- accepted -- sundial lupine
  Lupinus plattensis S. Watson -- accepted -- Nebraska lupine, Platte lupine
  Lupinus polyphyllus ssp. arcticus (S. Watson) L.L. Phillips -- not accepted
  Lupinus polyphyllus var. burkei (S. Watson) C.L. Hitchc. -- not accepted
  Lupinus rivularis var. latifolius (Lindl. ex J. Agardh) S. Watson -- not accepted
  Lupinus sellulus ssp. sellulus var. lobbii (A. Gray ex S. Watson) B.J. Cox -- not accepted -- Donner Lake lupine, Lobb's lupine
  Lupinus sellulus var. lobbii (A. Gray ex S. Watson) B.J. Cox -- accepted -- Donner Lake lupine
  Lupinus sericeus var. barbiger (S. Watson) S.L. Welsh -- not accepted
  Lupinus sericeus var. barbigeri (S. Watson) S.L. Welsh -- not accepted
  Lupinus shockleyi S. Watson -- accepted -- desert lupine, purple desert lupine
  Lupinus sileri S. Watson -- not accepted
  Lupinus sitgreavesii S. Watson -- not accepted
  Lupinus sparsiflorus var. arizonicus (S. Watson) C.P. Sm. -- not accepted
  Lupinus trifidus Torr. ex S. Watson -- not accepted
  Lupinus uncialis S. Watson -- accepted -- inchhigh lupine, Lilliput lupine
  Lupinus wyethi S. Watson -- not accepted
  Lupinus wyethi var. wyethi S. Watson -- not accepted
  Lupinus wyethii S. Watson -- accepted -- Wyeth's lupine
  Lupinus wyethii ssp. wyethii S. Watson -- accepted -- Wyeth's lupine
  Luzula acuminata ssp. carolinae (S. Watson) Z. Kaplan -- not accepted -- Carolina woodrush
  Luzula acuminata var. carolinae (S. Watson) Fernald -- accepted -- Carolina woodrush
  Luzula campestris var. macrantha (S. Watson) Fernald & Wiegand -- not accepted
  Luzula carolinae S. Watson -- not accepted
  Luzula comosa var. congesta (Thuill.) S. Watson -- not accepted
  Luzula comosa var. macrantha S. Watson -- not accepted
  Luzula comosa var. subsessilis S. Watson -- not accepted
  Luzula divaricata S. Watson -- accepted -- forked woodrush
  Luzula parviflora ssp. divaricata (S. Watson) Hultén -- not accepted
  Luzula parviflora var. divaricata (S. Watson) B. Boivin -- not accepted
  Luzula subcongesta (S. Watson) Jeps. -- accepted -- Donner woodrush
  Luzula subsessilis (S. Watson) Buchenau -- accepted
  Lychnis apetala ssp. montana (S. Watson) Maguire -- not accepted
  Lychnis apetala var. kingii (S. Watson) S.L. Welsh -- not accepted
  Lychnis apetala var. montana (S. Watson) C.L. Hitchc. -- not accepted
  Lychnis drummondii (Hook.) S. Watson -- not accepted
  Lychnis kingii S. Watson -- not accepted
  Lychnis montana S. Watson -- not accepted
  Lyrocarpa coulteri var. palmeri (S. Watson) Rollins -- not accepted -- Palmer's lyrepod
  Machaeranthera tenuis (S. Watson) B.L. Turner & Horne -- not accepted
  Malacothamnus densiflorus (S. Watson) Greene -- accepted -- dense-flowered bushmallow, yellowstem bushmallow
  Malacothamnus foliosus (S. Watson) Kearney -- accepted -- monarch bushmallow
  Malacothamnus palmeri (S. Watson) Greene -- accepted -- Palmer's bushmallow, Santa Lucia bushmallow
  Malacothamnus palmeri var. palmeri (S. Watson) Greene -- not accepted -- Palmer bush-mallow
  Malaxis corymbosa (S. Watson) Kuntze -- not accepted -- Huachuca adder's-mouth, Huachuca Mountain adder's-mouth orchid
  Malaxis tenuis (S. Watson) Ames -- not accepted -- Arizona adder's-mouth orchid, Arizona addersmouth orchid
  Malperia S. Watson -- accepted -- malperia
  Malperia tenuis S. Watson -- accepted -- brownturbans
  Malva occidentalis (S. Watson) M.F. Ray -- accepted
  Malvastrum bicuspidatum (S. Watson) Rose -- accepted -- shrubby false mallow, Sonoran Desert false mallow
  Malvastrum coulteri S. Watson -- not accepted
  Malvastrum densiflorum S. Watson -- not accepted
  Malvastrum palmeri S. Watson -- not accepted
  Malvastrum rugelii S. Watson -- not accepted
  Malvastrum tricuspidatum var. bicuspidatum S. Watson -- not accepted
  Marah guadalupensis (S. Watson) Greene -- accepted -- island manroot
  Marina orcuttii (S. Watson) Barneby -- accepted -- Sonoran false prairie-clover
  Marina orcuttii var. orcuttii (S. Watson) Barneby -- accepted -- California marina
  Mariosousa millefolia (S. Watson) Seigler & Ebinger -- accepted -- milfoil wattle
  Mariscus californicus (S. Watson) Fernald -- not accepted
  Maxia howellii (S. Watson) Ö. Nilsson -- not accepted
  Megapterium fremontii (S. Watson) Britton -- not accepted
  Megarrhiza guadalupensis S. Watson -- not accepted
  Megarrhiza oregana (Torr. & A. Gray) S. Watson -- not accepted
  Meibomia arizonica (S. Watson) Vail -- not accepted
  Melandrium kingii (S. Watson) Tolm. -- not accepted
  Melanthium parviflorum (Michx.) S. Watson -- not accepted -- Appalachian bunchflower
  Mentzelia brandegeei S. Watson -- not accepted
  Mentzelia dispersa S. Watson -- accepted -- bushy blazingstar, Nevada blazingstar, scattered blazingstar
  Mentzelia dispersa var. dispersa S. Watson -- accepted -- bushy blazingstar
  Mentzelia hirsutissima S. Watson -- accepted -- hairy blazingstar
  Mentzelia involucrata S. Watson -- accepted -- white bract stickleaf, whitebract blazingstar
  Mentzelia involucrata var. involucrata S. Watson -- accepted -- whitebract blazingstar, whitebract stickleaf
  Mertensia brevistyla S. Watson -- accepted -- shortstyle bluebells
  Mertensia lanceolata var. nivalis (S. Watson) Higgins -- not accepted -- greenleaf bluebells
  Mertensia paniculata var. nivalis S. Watson -- not accepted
  Mesyniopsis kingii (S. Watson) W.A. Weber -- not accepted
  Metastelma palmeri S. Watson -- accepted
  Micranthes eriophora (S. Watson) Small -- accepted -- redfuzz saxifrage
  Micranthes occidentalis (S. Watson) Small -- accepted -- Alberta saxifrage, redwool saxifrage, western saxifrage
  Micromonolepis pusilla (Torr. ex S. Watson) Ulbr. -- accepted -- small povertyweed
  Miltitzia glandulifera (Torr. ex S. Watson) A. Heller -- not accepted
  Mimulus deflexus S. Watson -- not accepted
  Mimulus filicaulis S. Watson -- accepted -- Hetch Hetchy monkey-flower, slenderstem monkeyflower
  Mimulus pilosus (Benth.) S. Watson -- accepted -- false monkeyflower
  Mimulus rubellus var. latiflorus S. Watson -- not accepted
  Minuartia howellii (S. Watson) Mattf. -- accepted -- Howell's stitchwort
  Minuartia pusilla (S. Watson) Mattf. -- accepted -- annual sandwort, dwarf sandwort
  Minuartia pusilla var. pusilla (S. Watson) Mattf. -- not accepted -- annual sandwort
  Mirabilis alipes (S. Watson) Pilz -- accepted -- winged four o'clock, winged four-o'clock
  Mirabilis glabra (S. Watson) Standl. -- accepted -- smooth four o'clock, smooth four-o'clock
  Mirabilis greenei S. Watson -- accepted -- Greene's four o'clock
  Mirabilis multiflora var. pubescens S. Watson -- accepted -- Colorado four o'clock
  Mirabilis tenuiloba S. Watson -- accepted -- longlobe four o'clock
  Mirabilis tenuiloba var. tenuiloba S. Watson -- accepted
  Monardella macrantha var. tenuiflora S. Watson ex A. Gray -- not accepted
  Monardella nana ssp. tenuiflora (S. Watson ex A. Gray) Abrams -- accepted -- yellow monardella
  Monolepis pusilla Torr. ex S. Watson -- not accepted -- small monolepis, small povertyweed
  Montia cordifolia (S. Watson) Pax & K. Hoffm. -- not accepted
  Montia howellii S. Watson -- accepted -- Howell's minerslettuce, Howell's montia
  Muhlenbergia filiformis (Thurb. ex S. Watson) Rydb. -- accepted -- pullup muhly
  Muhlenbergia filiformis var. filiformis (Thurb. ex S. Watson) Rydb. -- accepted -- pullup muhly
  Muhlenbergia foliosa ssp. setiglumis (S. Watson) Scribn. -- not accepted
  Muhlenbergia mexicana f. setiglumis (S. Watson) Fernald -- not accepted
  Muhlenbergia scabra S. Watson -- not accepted
  Muhlenbergia setiglumis (S. Watson) A. Nelson & J.F. Macbr. -- not accepted
  Muhlenbergia sylvatica var. setiglumis S. Watson -- not accepted
  Muilla S. Watson ex Benth. -- accepted -- muilla
  Muilla clevelandii (S. Watson) Hoover -- not accepted -- San Diego goldenstar
  Muilla maritima (Torr.) S. Watson -- accepted -- sea muilla
  Myosurus cupulatus S. Watson -- accepted -- Arizona mousetail
  Myosurus sessilis S. Watson -- accepted -- vernal pool mousetail
  Myrica hartwegii S. Watson -- accepted -- Sierra bayberry, Sierra sweet-bay
  Nasturtium curvisiliqua var. nuttallii S. Watson -- not accepted
  Nasturtium gambelii (S. Watson) O.E. Schulz -- accepted -- Gambel's yellowcress
  Nasturtium gambellii (S. Watson) O.E. Schulz -- not accepted -- Gambel's yellowcress
  Nasturtium obtusum var. alpinum S. Watson -- not accepted
  Nasturtium sinuatum var. columbiae S. Watson -- not accepted
  Nemastylis pringlei S. Watson -- not accepted
  Nemastylis tenuis (Herb.) S. Watson -- accepted -- southwestern pleatleaf
  Nemastylis tenuis ssp. pringlei (S. Watson) Goldblatt -- accepted -- Pringle's pleatleaf, southwestern pleatleaf
  Nemastylis tenuis ssp. tenuis (Herb.) S. Watson -- accepted
  Nemastylis tenuis var. pringlei (S. Watson) R.C. Foster -- not accepted
  Nemastylus tenuis var. pringlei (S. Watson) Goldblatt -- not accepted
  Nemastylus tenuis var. tenuis (Herb.) S. Watson -- not accepted
  Nerisyrenia linearifolia (S. Watson) Greene -- accepted -- White Sands fanmustard
  Nicotiana attenuata Torr. ex S. Watson -- accepted -- coyote tabacco, coyote tobacco
  Nicotiana bigelovii (Torr.) S. Watson -- not accepted
  Nissolia platycalyx S. Watson -- accepted -- broadsepal yellowhood
  Nitrophila S. Watson -- accepted -- niterwort
  Nitrophila occidentalis (Moq.) S. Watson -- accepted -- boraxweed, western niterwort
  Noccaea fendleri ssp. californica (S. Watson) Al-Shehbaz & M. Koch -- accepted -- Kneeland Prairie pennycress
  Nolina bigelovii (Torr.) S. Watson -- accepted -- Bigelow nolina, Bigelow's nolina, Palmilla de culebra
  Nolina bigelovii var. bigelovii (Torr.) S. Watson -- not accepted -- Bigelow's nolina
  Nolina bigelovii var. parryi (S. Watson) L.D. Benson -- not accepted
  Nolina erumpens (Torr.) S. Watson -- accepted -- beargrass, foothill beargrass, Palmilla de Chihuahua
  Nolina greenei S. Watson ex Trel. -- accepted -- woodland beargrass
  Nolina lindheimerana (Scheele) S. Watson -- not accepted
  Nolina lindheimeriana (Scheele) S. Watson -- accepted -- devil's shoestring, lindheimer nolina
  Nolina microcarpa S. Watson -- accepted -- Palmilla sacahuista, sacahuista
  Nolina parryi S. Watson -- accepted -- Palmilla de Parry, Parry's beargrass, Parry's sacahuista
  Nolina texana S. Watson -- accepted -- Palmilla texana, sacahuista, Texas sacahuista
  Oenothera alyssoides var. villosa S. Watson -- not accepted
  Oenothera biennis var. hirsutissima A. Gray ex S. Watson -- not accepted
  Oenothera caespitosa ssp. purpurea (S. Watson) Munz -- not accepted
  Oenothera caespitosa var. purpurea (S. Watson) Munz -- not accepted
  Oenothera californica (S. Watson) S. Watson -- accepted -- California evening primrose, California evening-primrose, California eveningprimrose
  Oenothera californica ssp. californica (S. Watson) S. Watson -- accepted -- California evening primrose, California evening-primrose
  Oenothera cespitosa ssp. purpurea (S. Watson) Munz -- not accepted
  Oenothera cespitosa var. purpurea (S. Watson) Munz -- not accepted
  Oenothera cheiranthifolia ssp. suffruticosa (S. Watson) Munz -- not accepted
  Oenothera cheiranthifolia var. suffruticosa (S. Watson) Munz -- not accepted
  Oenothera claviformis var. purpurascens (S. Watson) Munz -- not accepted
  Oenothera contorta var. pubens (S. Watson) Coville -- not accepted
  Oenothera cruciata (S. Watson) Munz -- not accepted
  Oenothera deltoides ssp. ambigua (S. Watson) W.M. Klein -- accepted -- birdcage evening primrose, birdcage evening-primrose, birdcage eveningprimrose
  Oenothera deltoides var. decumbens (S. Watson) Munz -- not accepted
  Oenothera elata ssp. hirsutissima (A. Gray ex S. Watson) W. Dietr. -- accepted -- Hooker's evening primrose, Hooker's evening-primrose, Hooker's eveningprimrose
  Oenothera elata var. hirsutissima (A. Gray ex S. Watson) Cronquist -- not accepted
  Oenothera fremontii S. Watson -- not accepted
  Oenothera fremontii var. fremontii S. Watson -- not accepted
  Oenothera fruticosa var. linearis (Michx.) S. Watson -- not accepted
  Oenothera guadalupensis S. Watson -- not accepted
  Oenothera havardii S. Watson -- accepted -- Havard's evening primrose, Havard's evening-primrose, Havard's eveningprimrose
  Oenothera heterochroma S. Watson -- not accepted
  Oenothera hookeri ssp. hirsutissima (A. Gray ex S. Watson) Munz -- not accepted
  Oenothera hookeri var. hirsutissima (A. Gray ex S. Watson) Munz -- not accepted
  Oenothera laciniata var. grandiflora (S. Watson) B.L. Rob. -- not accepted
  Oenothera macrocarpa ssp. fremontii (S. Watson) W.L. Wagner -- accepted -- Fremont's evening primrose, Fremont's evening-primrose
  Oenothera multijuga S. Watson -- not accepted
  Oenothera multijuga var. parviflora (S. Watson) Munz -- not accepted
  Oenothera oakesiana (A. Gray) J.W. Robbins ex S. Watson & J.M. Coult. -- accepted -- Oakes' evening primrose, Oakes' evening-primrose
  Oenothera palmeri S. Watson -- not accepted
  Oenothera parryi S. Watson -- not accepted
  Oenothera pterosperma S. Watson -- not accepted
  Oenothera pubens (S. Watson) Munz -- not accepted
  Oenothera refracta S. Watson -- not accepted
  Oenothera scapoidea var. purpurascens S. Watson -- not accepted
  Oenothera strigulosa var. pubens S. Watson -- not accepted
  Oligosporus dracunculus ssp. dracunculinus (S. Watson) W.A. Weber -- not accepted
  Oreocarya fulvocanescens (S. Watson) Greene -- not accepted
  Oreonana vestita (S. Watson) Jeps. -- accepted -- woolly mountainparsley
  Orobanche dugesii (S. Watson) Munz -- accepted -- Duges' broomrape
  Orogenia S. Watson -- accepted -- Indian potato
  Orogenia fusiformis S. Watson -- accepted -- California Indian potato
  Orogenia linearifolia S. Watson -- accepted -- Great Basin Indian potato, Indianpotato
  Orthocarpus imbricatus Torr. ex S. Watson -- accepted -- mountain owl's-clover
  Orthocarpus pilosus S. Watson -- not accepted
  Orthocarpus purpurascens var. latifolius S. Watson -- not accepted
  Orthocarpus purpureoalbus A. Gray ex S. Watson -- accepted -- purple owlclover, purplewhite owl's-clover, purplewhite owlclover
  Oryctes S. Watson -- accepted
  Oryctes nevadensis S. Watson -- accepted -- Nevada oryctes
  Oxybaphus glaber S. Watson -- not accepted
  Oxytheca hirtiflora (A. Gray ex S. Watson) Greene -- not accepted
  Oxytheca inermis S. Watson -- not accepted
  Pachycereus pecten-aboriginum (Engelm. ex S. Watson) Britton & Rose -- accepted
  Pachycereus pringlei (S. Watson) Britton & Rose -- accepted
  Panicularia grandis (S. Watson) Nash -- not accepted
  Panicum dichotomum var. commune S. Watson & J.M. Coult. -- not accepted
  Panicum scoparium S. Watson ex Nash -- not accepted
  Pappophorum wrightii S. Watson -- not accepted
  Parkinsonia florida (Benth. ex A. Gray) S. Watson -- accepted -- blue palo verde, blue paloverde
  Parkinsonia texana (A. Gray) S. Watson -- accepted -- Texas paloverde
  Parkinsonia texana var. texana (A. Gray) S. Watson -- accepted -- Texas paloverde
  Paronychia wilkinsonii S. Watson -- accepted -- Wilkinson's nailwort, Wilkinson's whitlow-wort
  Paspalum elliottii S. Watson -- not accepted
  Pectis palmeri S. Watson -- not accepted
  Pedicularis furbishiae S. Watson -- accepted -- Furbish lousewort, Furbish's lousewort, St. Johns River lousewort
  Pediomelum californicum (S. Watson) Rydb. -- accepted -- California Indian breadroot
  Pediomelum castoreum (S. Watson) Rydb. -- accepted -- Beaver Dam scurfpea, Beaver Indian breadroot
  Pediomelum mephiticum (S. Watson) Rydb. -- accepted -- skunktop
  Pediomelum reverchonii (S. Watson) Rydb. -- accepted -- rock Indian breadroot, rock scurfpea
  Penstemon haydenii S. Watson -- accepted -- blowout beardtongue, blowout penstemon
  Penstemon kingii S. Watson -- accepted -- King's beardtongue, King's penstemon
  Perideridia oregana (S. Watson) Mathias -- accepted -- Oregon yampah, squaw potato
  Perityle megalocephala (S. Watson) J.F. Macbr. -- accepted -- bighead rockdaisy, limestone rockdaisy, Nevada rockdaisy
  Perityle megalocephala var. megalocephala (S. Watson) J.F. Macbr. -- accepted -- limestone rockdaisy, Nevada rockdaisy
  Persicaria muehlenbergii (S. Watson) Small -- not accepted
  Persicaria muhlenbergii (S. Watson) Small -- not accepted
  Petalonyx nitidus S. Watson -- accepted -- shinyleaf sandpaper plant, shinyleaf sandpaperplant, smooth sandpaper plant
  Petalostemon flavescens S. Watson -- not accepted
  Petalostemon reverchonii S. Watson -- not accepted
  Petalostemon sabinalis S. Watson -- not accepted
  Petalostemon scariosus (S. Watson) Wemple -- not accepted
  Peteria thompsoniae S. Watson -- accepted -- Thompson's peteria
  Petrophyton caespitosum var. elatius (S. Watson) Tidestr. -- not accepted -- mat rockspirea, Rocky Mountain rockspirea
  Petrophytum caespitosum var. elatius (S. Watson) Tidestr. -- not accepted -- mat rockspirea
  Peucedanum graveolens S. Watson -- not accepted
  Peucedanum graveolens var. alpinum S. Watson -- not accepted
  Peucedanum kingii S. Watson -- not accepted
  Peucedanum kingii var. alpinum (S. Watson) J.M. Coult. & Rose -- not accepted
  Phacelia bicolor Torr. ex S. Watson -- accepted -- twocolor phacelia
  Phacelia bicolor var. bicolor Torr. ex S. Watson -- not accepted
  Phacelia covillei S. Watson -- accepted -- Coville's phacelia
  Phacelia crassifolia Torr. ex S. Watson -- not accepted
  Phacelia crenulata Torr. ex S. Watson -- accepted -- caterpillarweed, cleftleaf wildheliotrope, notch-leaf scorpion-weed
  Phacelia crenulata var. crenulata Torr. ex S. Watson -- accepted -- cleftleaf wildheliotrope
  Phacelia curvipes Torr. ex S. Watson -- accepted -- Washoe phacelia, Washoe scorpion-weed
  Phacelia glaberrima (Torr. ex S. Watson) J.T. Howell -- accepted -- Reese River phacelia, southwestern phacelia
  Phacelia gymnoclada Torr. ex S. Watson -- accepted -- nakedstem phacelia
  Phacelia lutea var. glandulifera (Torr. ex S. Watson) Cronquist -- not accepted
  Phacelia palmeri Torr. ex S. Watson -- accepted -- Palmer's phacelia, Palmer's scorpion-weed, Palmer's scorpionweed
  Phacelia rotundifolia Torr. ex S. Watson -- accepted -- natalgrass, round-leaf scorpion-weed, roundleaf phacelia
  Phaseolus polymorphus S. Watson -- accepted -- variable bean
  Phaseolus thompsonae S. Watson -- not accepted
  Phemeranthus brevicaulis (S. Watson) Kiger -- accepted -- dwarf fameflower
  Phippsia airoides (S. Watson & J.M. Coult.) Á. Löve & D. Löve -- not accepted
  Phoenicaulis cheiranthoides ssp. lanuginosa (S. Watson) Abrams -- not accepted
  Phoenicaulis cheiranthoides var. lanuginosa (S. Watson) Rollins -- not accepted
  Phyllospadix torreyi S. Watson -- accepted -- Torrey's surfgrass
  Physaria arizonica (S. Watson) O'Kane & Al-Shehbaz -- accepted -- Arizona bladderpod
  Physaria berlandieri (S. Watson) O'Kane & Al-Shehbaz -- accepted
  Physaria cinerea (S. Watson) O'Kane & Al-Shehbaz -- accepted -- basin bladderpod
  Physaria douglasii (S. Watson) O'Kane & Al-Shehbaz -- accepted -- Douglas' bladderpod
  Physaria douglasii ssp. douglasii (S. Watson) O'Kane & Al-Shehbaz -- accepted -- Douglas' bladderpod
  Physaria intermedia (S. Watson) O'Kane & Al-Shehbaz -- accepted -- mid bladderpod
  Physaria kingii (S. Watson) O'Kane & Al-Shehbaz -- accepted -- King bladderpod
  Physaria kingii ssp. kingii (S. Watson) O'Kane & Al-Shehbaz -- accepted -- King bladderpod
  Physaria occidentalis (S. Watson) O'Kane & Al-Shehbaz -- accepted -- western bladderpod
  Physaria occidentalis ssp. occidentalis (S. Watson) O'Kane & Al-Shehbaz -- accepted -- western bladderpod
  Physaria oregona S. Watson -- accepted -- Oregon twinpod
  Physaria palmeri (S. Watson) O'Kane & Al-Shehbaz -- accepted -- bladder pod
  Physaria sessilis (S. Watson) O'Kane & Al-Shehbaz -- accepted -- sessile bladderpod
  Physocarpus torreyi (S. Watson) Maxim. -- not accepted
  Picea breweriana S. Watson -- accepted -- Brewer spruce, weeping spruce
  Pinus contorta ssp. latifolia (Engelm. ex S. Watson) Critchfield -- not accepted -- black pine, Rocky Mountain lodgepole pine
  Pinus contorta var. latifolia Engelm. ex S. Watson -- accepted -- lodgepole pine, Rocky Mountain lodgepole pine, tall lodgepole pine
  Pinus divaricata var. latifolia (Engelm. ex S. Watson) B. Boivin -- not accepted
  Pinus radiata var. binata auct. non (S. Watson) Lemmon -- not accepted
  Piperia cooperi (S. Watson) Rydb. -- not accepted -- Cooper's rein orchid
  Pisonia capitata (S. Watson) Standl. -- accepted -- Mexican devil's-claws
  Pithecellobium sonorae S. Watson -- not accepted
  Plagiobothrys kingii (S. Watson) A. Gray -- accepted -- Great Basin popcornflower
  Plagiobothrys kingii var. kingii (S. Watson) A. Gray -- accepted -- Great Basin popcornflower, King's popcornflower
  Platanthera cooperi (S. Watson) R.M. Bateman -- accepted
  Platanthera sparsiflora (S. Watson) Schltr. -- accepted -- canyon bog orchid, Platanthera de pocas flores, sparse-flowered bog orchid
  Platanthera sparsiflora var. sparsiflora (S. Watson) Schltr. -- not accepted -- canyon bog orchid, sparse-flowered bog orchid
  Platanus racemosa var. wiightii (S. Watson) L.D. Benson -- not accepted
  Platanus racemosa var. wrightii (S. Watson) L.D. Benson -- not accepted
  Platanus wrightii S. Watson -- accepted -- Arizona sycamore
  Poa andina Nutt. ex S. Watson -- not accepted
  Poa eatonii S. Watson -- not accepted
  Poa kingii S. Watson -- not accepted
  Poa tenuifolia Nutt. ex S. Watson -- not accepted
  Podistera S. Watson -- accepted
  Podistera nevadensis (A. Gray) S. Watson -- accepted -- Nevada podistera
  Polemonium pauciflorum S. Watson -- accepted -- fewflower Jacob's-ladder
  Polemonium pauciflorum ssp. pauciflorum S. Watson -- accepted -- fewflower Jacob's-ladder
  Polyctenium fremontii (S. Watson) Greene -- accepted -- desert combleaf, Fremont's combleaf
  Polyctenium fremontii var. fremontii (S. Watson) Greene -- not accepted -- Fremont's combleaf
  Polygala alba var. suspecta S. Watson -- not accepted
  Polygala palmeri S. Watson -- accepted -- Palmer's milkwort
  Polygala subspinosa S. Watson -- not accepted -- spiny milkwort, spiny polygala
  Polygonum bidwelliae S. Watson -- accepted -- Bidwell knotweed, Bidwell's knotweed
  Polygonum bistortoides var. linearifolium (S. Watson) Small -- not accepted
  Polygonum greenii S. Watson -- not accepted
  Polygonum minimum S. Watson -- accepted -- broadleaf knotweed, dwarf knotweed, zigzag knotweed
  Polygonum muehlenbergii S. Watson -- not accepted
  Polygonum muhlenbergii S. Watson -- not accepted
  Polyodon texanus (S. Watson) Nash -- not accepted
  Populus balsamifera var. angustifolia (E. James) S. Watson -- not accepted
  Populus balsamifera var. augustifolia (E. James) S. Watson -- not accepted
  Populus balsamifera var. californica S. Watson -- not accepted
  Populus canadensis var. fremontii (S. Watson) Kuntze -- not accepted
  Populus deltoides ssp. wislizeni (S. Watson) Eckenw. -- accepted -- Rio Grande cottonwood
  Populus deltoides var. wislizeni (S. Watson) Dorn -- not accepted
  Populus deltoides var. wislizenii (S. Watson) Eckenw. -- not accepted
  Populus fremontii S. Watson -- accepted -- cottonwood, Fremont's cottonwood
  Populus fremontii ssp. fremontii S. Watson -- accepted -- Fremont's cottonwood
  Populus fremontii var. wislizeni S. Watson -- not accepted
  Populus trichocarpa var. cupulata S. Watson -- not accepted
  Populus wislizeni (S. Watson) Sarg. -- not accepted
  Potentilla baileyi (S. Watson) Greene -- not accepted
  Potentilla baileyi var. setosa (S. Watson) J.T. Howell -- not accepted
  Potentilla bolanderi var. parryi (S. Watson) Munz & I.M. Johnst. -- not accepted
  Potentilla breweri S. Watson -- accepted
  Potentilla breweri var. expansa S. Watson -- not accepted
  Potentilla concinna var. dissecta (S. Watson) B. Boivin -- not accepted
  Potentilla crinita var. lemmonii (S. Watson) Kearney & Peebles -- not accepted -- Lemmon's cinquefoil
  Potentilla decurrens (S. Watson) Rydb. -- not accepted
  Potentilla dissecta var. decurrens S. Watson -- not accepted
  Potentilla diversifolia var. decurrens (S. Watson) Th. Wolf -- not accepted
  Potentilla diversifolia var. glaucophylla (Lehm.) S. Watson -- not accepted
  Potentilla diversifolia var. multisecta S. Watson -- not accepted
  Potentilla douglasii var. tenella (S. Watson) Greene -- not accepted -- pinewoods horkelia
  Potentilla drummondii ssp. breweri (S. Watson) Ertter -- not accepted -- Brewer's cinquefoil, Drummond's cinquefoil
  Potentilla drummondii var. breweri (S. Watson) N.H. Holmgren -- not accepted
  Potentilla flabellifolia var. grayi (S. Watson) Jeps. -- not accepted
  Potentilla glandulosa ssp. nevadensis (S. Watson) D.D. Keck -- not accepted -- Nevada cinquefoil
  Potentilla glandulosa var. nevadensis S. Watson -- not accepted
  Potentilla gracilis var. fastigiata (Nutt.) S. Watson -- accepted -- northwest cinquefoil, Nuttall's cinquefoil, slender cinquefoil
  Potentilla gracilis var. rigida S. Watson -- not accepted
  Potentilla grayi S. Watson -- accepted -- Gray's cinquefoil
  Potentilla kingii (S. Watson) Greene -- not accepted
  Potentilla lemmonii (S. Watson) Greene -- not accepted
  Potentilla multisecta (S. Watson) Rydb. -- accepted -- alpine cinquefoil, featherleaf cinquefoil
  Potentilla nicolletii (S. Watson) Sheldon -- not accepted
  Potentilla nivea var. dissecta S. Watson -- not accepted
  Potentilla ovina var. decurrens (S. Watson) S.L. Welsh & B.C. Johnst. -- accepted -- sheep cinquefoil
  Potentilla ovina var. pinnatisecta S. Watson -- not accepted
  Potentilla pensylvanica var. glabrata (Lehm. ex Hook.) S. Watson -- not accepted
  Potentilla purpurascens (S. Watson) Greene -- not accepted
  Potentilla rivalis var. millegrana (Engelm. ex Lehm.) S. Watson -- not accepted -- brook cinquefoil
  Potentilla rivalis var. pentandra (Engelm. ex Torr. & A. Gray) S. Watson -- not accepted -- brook cinquefoil, cinquefoil
  Potentilla sericata (S. Watson) Greene -- not accepted
  Potentilla shockleyi (S. Watson) Jeps. -- not accepted
  Potentilla supina var. nicollettii S. Watson -- not accepted
  Potentilla utahensis (S. Watson) Greene -- not accepted
  Potentilla wheeleri S. Watson -- accepted -- Kern cinquefoil
  Potentilla wheeleri var. wheeleri S. Watson -- not accepted -- Wheeler's cinquefoil
  Prosartes hookeri var. oregana (S. Watson) Kartesz -- not accepted -- Oregon drops of gold
  Prosartes hookeri var. parvifolia (S. Watson) Kartesz -- not accepted -- drops of gold
  Prosartes oregana S. Watson -- not accepted
  Prosartes parvifolia S. Watson -- not accepted
  Prosartes trachycarpa S. Watson -- accepted -- roughfruit fairybells
  Prosopis articulata S. Watson -- not accepted -- velvet mesquite
  Prosopis juliflora var. articulata (S. Watson) Wiggins -- not accepted
  Prosopis palmeri S. Watson -- accepted -- mesquite
  Prunus fremontii S. Watson -- accepted -- desert apricot
  Prunus mexicana S. Watson -- accepted -- Mexican plum
  Pseudotrillium rivale (S. Watson) S.B. Farmer -- accepted -- brook wakerobin
  Psilactis tenuis S. Watson -- accepted -- slender tansyaster
  Psoralea californica S. Watson -- not accepted
  Psoralea castorea S. Watson -- not accepted
  Psoralea mephitica S. Watson -- not accepted
  Psoralea reverchonii S. Watson -- not accepted
  Psorothamnus kingii (S. Watson) Barneby -- accepted -- King's dalea
  Psorothamnus polydenius (Torr. ex S. Watson) Rydb. -- accepted -- Nevada dalea
  Psorothamnus polydenius var. polydenius (Torr. ex S. Watson) Rydb. -- accepted -- Nevada dalea, Nevada smokebush
  Puccinellia airoides S. Watson & J.M. Coult. -- not accepted
  Puccinellia distans var. minor (S. Watson) B. Boivin -- not accepted
  Puccinellia maritima var. minor S. Watson -- not accepted
  Pulsatilla occidentalis (S. Watson) Freyn -- not accepted -- white pasqueflower
  Pyrus occidentalis S. Watson -- not accepted
  Quamoclidion greenei (S. Watson) Standl. -- not accepted
  Racomitrium neevii (Müll. Hal.) S. Watson -- not accepted
  Randia obcordata S. Watson -- accepted
  Ranunculus adoneus var. alpinus (S. Watson) L.D. Benson -- not accepted -- alpine buttercup
  Ranunculus alismifolius var. montanus S. Watson -- accepted -- waterplantain buttercup
  Ranunculus ambigens S. Watson -- accepted -- waterplantain spearwort
  Ranunculus andersonii var. tenellus S. Watson -- not accepted -- Anderson's buttercup, desert buttercup
  Ranunculus aquatilis var. lobbii (Hiern) S. Watson -- not accepted
  Ranunculus bloomeri S. Watson -- not accepted
  Ranunculus eschscholtzii var. alpinus (S. Watson) C.L. Hitchc. -- not accepted
  Ranunculus nivalis var. eschscholtzii (Schltdl.) S. Watson -- not accepted
  Ranunculus orthorhynchus var. alpinus S. Watson -- not accepted
  Ranunculus orthorhynchus var. bloomeri (S. Watson) L.D. Benson -- accepted -- Bloomer's buttercup
  Rhinotropis subspinosa (S. Watson) J.R. Abbott -- accepted
  Rhus aromatica var. trilobata (Nutt.) A. Gray ex S. Watson -- not accepted -- ill-scented sumac, skunkbush sumac
  Rhus integrifolia (Nutt.) Benth. & Hook. f. ex W.H. Brewer & S. Watson -- accepted -- lemonade sumac
  Rhus ovata S. Watson -- accepted -- sugar sumac
  Rhynchosia mollissima (Elliott) Shuttlew. ex S. Watson -- not accepted
  Ribes ambiguum S. Watson -- not accepted
  Ribes cereum var. pedicellare W.H. Brewer & S. Watson -- not accepted -- squaw currant, whisky currant, white squaw currant
  Rorippa alpina (S. Watson) Rydb. -- accepted -- alpine yellowcress
  Rorippa calycina var. columbiae (S. Watson) Rollins -- not accepted
  Rorippa columbiae (S. Watson) Howell -- accepted -- Columbia watercress, Columbian yellowcress
  Rorippa curvipes var. alpina (S. Watson) Stuckey -- not accepted
  Rorippa curvisiliqua var. nuttallii (S. Watson) Stuckey -- not accepted -- Nuttall's yellowcress
  Rorippa gambelii (S. Watson) Rollins & Al-Shehbaz -- not accepted -- Gambel's watercress, Gambel's yellowcress
  Rorippa gambellii (S. Watson) Rollins & Al-Shehbaz -- not accepted -- Gambel's watercress
  Rorippa islandica var. occidentalis (S. Watson) Butters & Abbe -- not accepted
  Rorippa obtusa var. alpina (S. Watson) Britton -- not accepted
  Rorippa palustris ssp. occidentalis (S. Watson) Abrams -- not accepted -- bog yellowcress, western bog yellowcress
  Rorippa palustris var. occidentalis (S. Watson) Rollins -- not accepted
  Rosa engelmannii S. Watson -- not accepted
  Rosa gymnocarpa var. pubescens S. Watson -- not accepted
  Rosa gymnocarpa var. pubescens S. Watson -- not accepted
  Rosa spaldingii var. parkeri (S. Watson) H. St. John -- not accepted
  Rosa spithamea S. Watson -- accepted -- ground rose
  Rosa spithamea var. spithamea S. Watson -- not accepted -- ground rose
  Rosa ultramontana (S. Watson) A. Heller -- not accepted
  Rosa woodsii ssp. ultramontana (S. Watson) Roy L. Taylor & MacBryde -- accepted -- Woods' rose
  Rosa woodsii var. ultramontana (S. Watson) Jeps. -- not accepted -- Woods' rose
  Rosa X engelmannii S. Watson (pro sp.) -- accepted
  Rotantha floridana (S. Watson ex A. Gray) Small -- not accepted
  Rubus spectabilis var. menziesii (Hook.) S. Watson -- not accepted
  Rumex aquaticus ssp. occidentalis (S. Watson) Hultén -- not accepted
  Rumex occidentalis S. Watson -- accepted -- western dock
  Ruppia cirrhosa ssp. occidentalis (S. Watson) Á. Löve & D. Löve -- not accepted
  Ruppia maritima var. occidentalis (S. Watson) Graebn. -- not accepted
  Ruppia occidentalis S. Watson -- not accepted
  Sageretia wrightii S. Watson -- accepted -- mock buckthorn, Wright's mock buckthorn
  Sagina crassicaulis S. Watson -- not accepted
  Sagina decumbens ssp. occidentalis (S. Watson) G.E. Crow -- accepted -- western pearlwort
  Sagina decumbens var. smithii (A. Gray) S. Watson -- not accepted
  Sagina maxima ssp. crassicaulis (S. Watson) G.E. Crow -- accepted -- stickystem pearlwort
  Sagina occidentalis S. Watson -- not accepted
  Sagittaria graminea var. teres (S. Watson) Bogin -- not accepted
  Sagittaria subulata var. gracillima (S. Watson) J.G. Sm. -- not accepted
  Sagittaria teres S. Watson -- accepted -- quill-leaved sagittaria, slender arrowhead
  Sairocarpus kingii (S. Watson) D.A. Sutton -- accepted -- King's snapdragon, least snapdragon, least toad's-mouth
  Salix exigua var. nevadensis (S. Watson) C.K. Schneid. -- not accepted
  Salix nevadensis S. Watson -- not accepted
  Sanicula maritima Kellogg ex S. Watson -- accepted -- adobe sanicle, adobe snakeroot
  Sanicula nevadensis S. Watson -- not accepted
  Sapium biloculare (S. Watson) Pax -- not accepted -- jumping-bean sapium, Mexican jumpingbean
  Saxifraga eriophora S. Watson -- not accepted -- redfuzz saxifrage
  Saxifraga occidentalis S. Watson -- not accepted -- Alberta saxifrage
  Saxifraga reflexa ssp. occidentalis (S. Watson) Hultén -- not accepted
  Schobera occidentalis S. Watson -- not accepted
  Schoberia occidentalis S. Watson -- not accepted
  Schoenolirion bracteosum (S. Watson) Jeps. -- not accepted
  Schoenoplectus acutus var. occidentalis (S. Watson) S.G. Sm. -- accepted -- tule
  Scirpus acutus var. occidentalis (S. Watson) Beetle -- not accepted
  Scirpus nevadensis S. Watson -- not accepted -- Nevada bulrush
  Scirpus occidentalis (S. Watson) Chase -- not accepted
  Scleropogon karwinskyanus (E. Fourn.) Benth. ex S. Watson -- not accepted
  Scoliopus hallii S. Watson -- accepted -- Oregon fetid adderstongue
  Sebastiania bilocularis S. Watson -- accepted -- arrow poison plant
  Sedum debile S. Watson -- accepted -- orpine stonecrop, weakstem stonecrop
  Sedum diffusum S. Watson -- accepted
  Sedum divergens S. Watson -- accepted -- Pacific stonecrop
  Sedum divericatum S. Watson -- not accepted
  Sedum douglasii ssp. radiatum (S. Watson) R.T. Clausen -- not accepted
  Sedum oregonense (S. Watson) M. Peck -- accepted -- cream stonecrop
  Sedum radiatum S. Watson -- accepted -- Coast Range stonecrop
  Sedum radiatum ssp. radiatum S. Watson -- not accepted -- Coast Range stonecrop
  Sedum radiatum var. radiatum S. Watson -- accepted -- Coast Range stonecrop
  Sedum stelliforme S. Watson -- accepted -- Huachuca Mountain stonecrop
  Sedum stenopetalum ssp. radiatum (S. Watson) R.T. Clausen -- not accepted
  Selenia aptera (S. Watson) Small -- not accepted
  Senna armata (S. Watson) H.S. Irwin & Barneby -- accepted -- desert senna, desertsenna
  Seutera palmeri (S. Watson) Fishbein & W.D. Stevens -- accepted
  Sibara runcinata (S. Watson) Rollins -- not accepted
  Sibara runcinata var. runcinata (S. Watson) Rollins -- not accepted -- Rio Grande winged rockcress
  Sida alata S. Watson -- not accepted
  Sidalcea hendersonii S. Watson -- accepted -- Henderson's checkerbloom, Henderson's checkermallow
  Sieglingia schaffneri (S. Watson) Kuntze -- not accepted
  Sieglingia texana (S. Watson) Kuntze -- not accepted
  Silene bernardina S. Watson -- accepted -- Palmer's campion, Palmer's catchfly
  Silene bernardina ssp. bernardina S. Watson -- not accepted -- Palmer's campion, Palmer's catchfly
  Silene campanulata S. Watson -- accepted -- Red Mountain catchfly
  Silene campanulata ssp. campanulata S. Watson -- accepted -- Red Mountain catchfly
  Silene campanulata ssp. greenei (S. Watson) C.L. Hitchc. & Maguire -- not accepted -- Greene's catchfly
  Silene campanulata var. greenei S. Watson -- not accepted
  Silene douglasii var. macounii (S. Watson) B.L. Rob. -- not accepted
  Silene douglasii var. monantha (S. Watson) B.L. Rob. -- not accepted
  Silene grayi S. Watson -- accepted -- Gray's catchfly, Maui catchfly
  Silene hallii S. Watson -- not accepted
  Silene kingii (S. Watson) Bocquet -- accepted -- King's campion
  Silene laciniata var. greggii (A. Gray) S. Watson -- not accepted
  Silene lemmonii S. Watson -- accepted -- Lemmon's catchfly
  Silene lyallii S. Watson -- not accepted
  Silene macounii S. Watson -- not accepted
  Silene montana S. Watson -- not accepted
  Silene montana ssp. bernardina (S. Watson) C.L. Hitchc. & Maguire -- not accepted
  Silene montana var. montana S. Watson -- not accepted
  Silene multinervia S. Watson -- not accepted -- manynerve catchfly
  Silene nuda (S. Watson) C.L. Hitchc. & Maguire -- accepted -- barestem campion, western fringed catchfly
  Silene nuda ssp. nuda (S. Watson) C.L. Hitchc. & Maguire -- not accepted -- western fringed campion, western fringed catchfly
  Silene occidentalis S. Watson -- accepted -- western catchfly
  Silene occidentalis ssp. occidentalis S. Watson -- not accepted -- western catchfly
  Silene oregana S. Watson -- accepted -- Oregon campion, Oregon silene
  Silene parishii S. Watson -- accepted -- Parish's catchfly
  Silene parishii var. parishii S. Watson -- not accepted -- Parish's catchfly
  Silene parryi (S. Watson) C.L. Hitchc. & Maguire -- accepted -- Parry's silene
  Silene pectinata S. Watson -- not accepted
  Silene platyota S. Watson -- not accepted
  Silene sargentii S. Watson -- accepted -- Sargent's campion, Sargent's catchfly
  Silene scouleri ssp. hallii (S. Watson) C.L. Hitchc. & Maguire -- accepted -- simple campion
  Silene scouleri ssp. pringlei (S. Watson) C.L. Hitchc. & Maguire -- accepted -- Pringle's catchfly, simple campion
  Silene scouleri ssp. pringlei var. pringlei (S. Watson) C.L. Hitchc. & Maguire ex Kartesz & Gandhi -- not accepted
  Silene scouleri var. macounii (S. Watson) B. Boivin -- not accepted
  Silene scouleri var. pringlei (S. Watson) C.L. Hitchc. & Maguire ex Kartesz & Gandhi -- not accepted -- simple campion
  Silene shockleyi S. Watson -- not accepted
  Silene spaldingii S. Watson -- accepted -- Spalding's catchfly, Spalding's silene
  Silene thurberi S. Watson -- accepted -- woolly catchfly
  Silene uralensis ssp. montana (S. Watson) McNeill -- not accepted -- apetalous catchfly
  Silene verecunda S. Watson -- accepted -- Delores' campion, San Francisco campion
  Silene verecunda ssp. platyota (S. Watson) C.L. Hitchc. & Maguire -- not accepted -- San Francisco campion
  Silene verecunda ssp. platyota var. platyota (S. Watson) Jeps. -- not accepted -- San Francisco campion
  Silene verecunda ssp. verecunda S. Watson -- not accepted -- Mission Dolores campion, San Francisco campion
  Silene verecunda var. platyota (S. Watson) Jeps. -- not accepted -- San Francisco campion
  Silene wahlbergella ssp. montana (S. Watson) Hultén -- not accepted
  Sisymbrium ambiguum (S. Watson) Payson -- not accepted
  Sisymbrium vaseyi S. Watson ex B.L. Rob. -- not accepted
  Sisyrinchium bellum S. Watson -- accepted -- western blue-eyed grass
  Smelowskia fremontii S. Watson -- not accepted
  Smilacina racemosa var. amplexicaulis (Nutt.) S. Watson -- not accepted
  Smilax ecirrata (Engelm. ex Kunth) S. Watson -- not accepted -- greenbriar, upright carrion-flower, upright carrionflower
  Smilax ecirrhata (Engelm. ex Kunth) S. Watson -- accepted -- upright carrionflower
  Sophora arizonica S. Watson -- not accepted -- Arizona necklacepod, Arizona sophora, mescalbean
  Sorbus occidentalis (S. Watson) Greene -- not accepted
  Spermolepis divaricata (Benth. & Hook. f. ex S. Watson) Raf. ex Ser. -- accepted -- forked scaleseed, roughfruit scaleseed
  Sphaeralcea coulteri (S. Watson) A. Gray -- accepted -- annual globemallow, Coulter's globemallow
  Sphaeralcea coulteri var. coulteri (S. Watson) A. Gray -- accepted
  Sphaeralcea densiflora (S. Watson) Jepson -- not accepted
  Sphinctospermum constrictum (S. Watson) Rose -- accepted -- hourglass peaseed
  Sphinotospermum constrictum (S. Watson) Rose -- not accepted
  Spiraea caespitosa var. elatior S. Watson -- not accepted
  Spiraea camtschatica var. occidentalis (S. Watson) Wenz. -- not accepted
  Spiraea occidentalis S. Watson -- not accepted
  Spiranthes praecox (Walter) S. Watson -- accepted -- greenvein ladies'-tresses, greenvein ladiestresses, greenvein lady's tresses
  Sporobolus filiformis (Thurb. ex S. Watson) Rydb. -- not accepted
  Sporobolus gracillimus (Thurb. ex S. Watson) Vasey -- not accepted
  Stanfordia S. Watson -- not accepted -- stanfordia
  Stanfordia californica S. Watson -- not accepted -- St. Francis cabbage
  Stellaria longifolia var. laeta (Richardson) S. Watson -- not accepted
  Stellaria longipes var. laeta (Richardson) S. Watson -- not accepted
  Stenanthium gramineum var. robustum (S. Watson) Fernald -- not accepted -- eastern featherbells
  Stenanthium robustum S. Watson -- not accepted
  Stillingia angustifolia (Müll. Arg.) Engelm. ex S. Watson -- not accepted
  Stillingia linearifolia S. Watson -- accepted -- narrowleaf stillingia, queen's-root
  Stillingia paucidentata S. Watson -- accepted -- Mojave toothleaf
  Stipa californica Vasey ex S. Watson -- not accepted
  Stipa occidentalis Thurb. ex S. Watson -- not accepted
  Streptanthella longirostris (S. Watson) Rydb. -- accepted -- longbeak fiddle mustard, longbeak streptanthella
  Streptanthus amplexicaulis (S. Watson) Jeps. -- not accepted
  Streptanthus arizonicus S. Watson -- not accepted
  Streptanthus barbatus S. Watson -- accepted -- Pacific jewelflower
  Streptanthus californicus (S. Watson) Greene -- not accepted
  Streptanthus campestris S. Watson -- accepted -- southern jewelflower
  Streptanthus carinatus ssp. arizonicus (S. Watson) Kruckeb., Rodman & Worth. -- accepted -- Arizona jewelflower, Arizona twistflower, lyreleaf jewelflower
  Streptanthus coulteri var. lemmonii (S. Watson) Jeps. -- not accepted
  Streptanthus diversifolius S. Watson -- accepted -- variableleaf jewelflower, variedleaf twistflower
  Streptanthus glaucus (S. Watson) Jeps. -- not accepted
  Streptanthus howellii S. Watson -- accepted -- Howell's jewelflower
  Streptanthus inflatus (S. Watson) Greene -- not accepted
  Streptanthus lemmonii S. Watson -- accepted -- Lemmon's jewelflower
  Streptanthus lemmonii (S. Watson) Jeps. -- not accepted
  Streptanthus pilosus (S. Watson) Jeps. -- not accepted
  Strophostyles helvula var. missouriensis (S. Watson) Britton -- not accepted
  Strophostyles pauciflora (Benth.) S. Watson -- not accepted
  Stylophyllum viscidum (S. Watson) Britton & Rose -- not accepted
  Suaeda californica S. Watson -- accepted -- California seablite
  Suaeda californica var. californica S. Watson -- not accepted -- California seablite
  Suaeda depressa auct. non (Pursh) S. Watson -- not accepted
  Suaeda depressa var. erecta S. Watson -- not accepted
  Suaeda intermedia S. Watson -- not accepted
  Suaeda minutiflora S. Watson -- not accepted
  Suaeda occidentalis (S. Watson) S. Watson -- accepted -- western seepweed
  Suaeda suffrutescens S. Watson -- not accepted -- desert seepweed
  Suaeda suffrutescens var. suffrutescens S. Watson -- not accepted -- desert seepweed
  Suaeda torreyana S. Watson -- not accepted
  Sullivantia gregana S. Watson -- not accepted
  Sullivantia oregana S. Watson -- accepted -- Oregon coolwort
  Swertia albomarginata (S. Watson) Kuntze -- not accepted
  Sympetaleia rupestris (Baill.) A. Gray ex S. Watson -- not accepted
  Synthyris pinnatifida S. Watson -- accepted -- featherleaf kittentails
  Synthyris pinnatifida var. pinnatifida S. Watson -- not accepted -- featherleaf kittentails
  Talinum brevicaule S. Watson -- not accepted -- dwarf fameflower
  Tephrosia affinis S. Watson -- not accepted
  Tephrosia constricta S. Watson -- not accepted
  Tetracoccus fasciculatus auct. non (S. Watson) Croizat -- not accepted -- purplebush
  Tetracoccus fasciculatus (S. Watson) Croizat -- accepted
  Tetrapteron palmeri (S. Watson) W.L. Wagner & Hoch -- accepted -- Palmer's evening primrose
  Thalictrum polycarpum (Torr.) S. Watson -- accepted
  Thelypodiopsis ambigua (S. Watson) Al-Shehbaz -- accepted -- long valley tumble-mustard, Long Valley tumblemustard
  Thelypodiopsis ambigua var. ambigua (S. Watson) Al-Shehbaz -- not accepted -- Long Valley tumblemustard, tumble-mustard
  Thelypodiopsis vaseyi (S. Watson ex B.L. Rob.) Rollins -- accepted -- Las Vegas tumblemustard
  Thelypodium ambiguum S. Watson -- not accepted
  Thelypodium cooperi S. Watson -- not accepted
  Thelypodium flavescens (Hook.) S. Watson -- not accepted
  Thelypodium howellii S. Watson -- accepted -- Howell's thelypody
  Thelypodium howellii ssp. howellii S. Watson -- accepted -- Howell's thelypody
  Thelypodium longifolium (Benth.) S. Watson -- not accepted
  Thelypodium micranthum (A. Gray) S. Watson -- not accepted
  Thelypodium pinnatifidum (Michx.) S. Watson -- not accepted
  Thelypodium stenopetalum S. Watson -- accepted -- slender-petaled mustard, slenderpetal thelypody
  Thermopsis californica S. Watson -- accepted -- California goldenbanner
  Thermopsis californica var. californica S. Watson -- accepted -- California goldenbanner
  Thlaspi californicum S. Watson -- not accepted -- Kneeland Prairie pennycress
  Thlaspi montanum var. californicum (S. Watson) P.K. Holmgren -- not accepted
  Thysanocarpus erectus S. Watson -- accepted
  Tidestromia oblongifolia (S. Watson) Standl. -- not accepted -- Arizona honeysweet, honeysweet tidestromia
  Tidestromia oblongifolia ssp. cryptantha (S. Watson) Wiggins -- not accepted -- Arizona honeysweet
  Tidestromia oblongifolia ssp. oblongifolia (S. Watson) Standl. -- not accepted -- Arizona honeysweet
  Tidestromia suffruticosa var. oblongifolia (S. Watson) Sánch. Pino & Flores Olv. -- accepted -- Arizona honeysweet
  Tillaea angustifolia var. bolanderi S. Watson -- not accepted
  Tillaea bolanderi (S. Watson) Greene -- not accepted
  Tillaea drummondii var. bolanderi (S. Watson) Jeps. -- not accepted
  Tillaea minima var. subsimplex S. Watson -- not accepted
  Tillaea viridis S. Watson -- not accepted
  Tillaeastrum viride (S. Watson) Britton -- not accepted
  Tiquilia mexicana (S. Watson) A.T. Richardson -- accepted -- Mexican coldenia, Mexican crinklemat
  Tithymalus palmeri (Engelm. ex S. Watson) Dayton -- not accepted
  Tithymalus subpubens (Engelm. ex S. Watson) Norton -- not accepted
  Tofieldia glutinosa ssp. occidentalis (S. Watson) C.L. Hitchc. -- not accepted -- western tofieldia
  Tofieldia glutinosa var. occidentalis (S. Watson) C.L. Hitchc. -- not accepted
  Tofieldia occidentalis S. Watson -- not accepted
  Toxicodendron radicans ssp. pubens (Engelm. ex S. Watson) Gillis -- accepted -- eastern poison ivy
  Toxicodendron radicans var. pubens (Engelm. ex S. Watson) Reveal -- not accepted
  Toxicoscordion venenosum (S. Watson) Rydb. -- accepted -- meadow deathcamas
  Toxicoscordion venenosum var. venenosum (S. Watson) Rydb. -- accepted -- meadow deathcamas
  Tradescantella floridana (S. Watson) Small -- not accepted
  Triantha occidentalis (S. Watson) R.R. Gates -- accepted -- western false asphodel
  Triantha occidentalis ssp. occidentalis (S. Watson) R.R. Gates -- accepted -- western false asphodel
  Tricardia Torr. ex S. Watson -- accepted
  Tricardia watsonii Torr. ex S. Watson -- accepted -- threehearts
  Tridens texanus (S. Watson) Nash -- accepted -- Texas fluffgrass, Texas tridens
  Trifolium beckwithii W.H. Brewer ex S. Watson -- accepted -- Beckwith's clover
  Trifolium brandegeei S. Watson -- accepted -- Brandegee's clover
  Trifolium breweri S. Watson -- accepted -- forest clover
  Trifolium catalinae S. Watson -- not accepted
  Trifolium depauperatum var. amplectens (Torr. & A. Gray) S. Watson -- accepted -- balloon sack clover
  Trifolium gracilentum var. palmeri (S. Watson) McDermott -- accepted -- Palmer's clover
  Trifolium gymnocarpon ssp. plummerae (S. Watson) J.M. Gillett -- accepted -- Plummer clover, Plummer's clover
  Trifolium gymnocarpon var. lemmonii (S. Watson) McDermott -- not accepted
  Trifolium gymnocarpon var. plummerae (S. Watson) J.S. Martin -- not accepted
  Trifolium howellii S. Watson -- accepted -- canyon clover
  Trifolium involucratum var. heterodon (Torr. & A. Gray) S. Watson -- not accepted
  Trifolium kingii S. Watson -- accepted -- King's clover
  Trifolium kingii ssp. kingii S. Watson -- accepted -- King's clover
  Trifolium kingii var. brandegeei (S. Watson) McDermott -- not accepted
  Trifolium lemmonii S. Watson -- accepted -- Lemmon's clover
  Trifolium longipes var. brachypus S. Watson -- not accepted
  Trifolium macraei var. dichotomum (Hook. & Arn.) W.H. Brewer ex S. Watson -- not accepted
  Trifolium palmeri S. Watson -- not accepted
  Trifolium plummerae S. Watson -- not accepted
  Trifolium tridentatum var. obtusiflorum (Hook.) S. Watson -- not accepted
  Trillium lanceolatum (S. Watson) Boykin ex Small -- not accepted
  Trillium recurvatum ssp. lanceolatum (S. Watson) E. Murray -- not accepted
  Trillium rivale S. Watson -- not accepted -- brook wakerobin
  Triodia schaffneri S. Watson -- not accepted
  Triodia texana S. Watson -- not accepted
  Triteleia bridgesii (S. Watson) Greene -- accepted -- Bridges' brodiaea
  Triteleia gracilis (S. Watson) Greene -- not accepted
  Triteleia grandiflora var. howellii (S. Watson) Hoover -- not accepted -- Howell's triteleia
  Triteleia howellii (S. Watson) Greene -- not accepted
  Triteleia lemmonae (S. Watson) Greene -- not accepted
  Triteleia lemmoniae (S. Watson) Greene -- accepted -- Oak Creek triplet-lily, Oak Creek triteleia
  Triteleiopsis palmeri (S. Watson) Hoover -- accepted -- Palmer's Baja-lily, Palmer's Bajalily
  Urtica breweri S. Watson -- not accepted
  Urtica dioica var. lyallii (S. Watson) C.L. Hitchc. -- not accepted
  Urtica dioica var. occidentalis S. Watson -- not accepted
  Urtica lyallii S. Watson -- not accepted
  Vaccinium X marianum S. Watson (pro sp.) -- not accepted
  Vachellia schaffneri (S. Watson) Seigler & Ebinger -- accepted -- Schaffner's wattle
  Valeriana dioica ssp. sylvatica (S. Watson) F.G. Mey. -- not accepted
  Valeriana dioica var. sylvatica S. Watson -- accepted -- woods valerian, woods valeriana
  Vaseyanthus insularis var. palmeri (S. Watson) Gentry -- not accepted
  Vicia americana var. linearis (Nutt.) S. Watson -- not accepted
  Vicia exigua var. hassei (S. Watson) Jeps. -- not accepted
  Vicia floridana S. Watson -- accepted -- Florida vetch
  Vicia hassei S. Watson -- accepted -- Hasse's vetch, slender vetch
  Vicia reverchonii S. Watson -- not accepted -- hairy pod vetch
  Vicia sparsifolia var. truncata (Nutt.) S. Watson -- not accepted
  Viguiera reticulata S. Watson -- not accepted -- Death Valley goldeneye, netvein goldeneye
  Vilfa depauperata var. filiformis Thurb. ex S. Watson -- not accepted
  Vilfa gracillima Thurb. ex S. Watson -- not accepted
  Villadia squamulosa (S. Watson) Rose -- accepted -- rat's-tail succulent, ratstail succulent
  Viola adunca ssp. oxyceras (S. Watson) Piper -- not accepted
  Viola adunca var. oxyceras (S. Watson) Jeps. -- not accepted -- hookedspur violet
  Viola cuneata S. Watson -- accepted -- wedgeleaf violet
  Viola lobata ssp. integrifolia (S. Watson) R.J. Little -- not accepted -- pine violet
  Viola lobata var. integrifolia S. Watson -- accepted -- pine violet
  Viola nuttallii var. praemorsa (Douglas ex Lindl.) S. Watson -- not accepted
  Viola oxyceras S. Watson -- not accepted
  Viola purpurea ssp. venosa (S. Watson) M.S. Baker & J.C. Clausen -- not accepted -- goosefoot violet, goosefoot yellow violet
  Viola purpurea var. venosa (S. Watson) Brainerd -- accepted -- goosefoot violet
  Viola venosa (S. Watson) Rydb. -- not accepted
  Viorna fremontii (S. Watson) A. Heller -- not accepted
  Wahlbergella kingii (S. Watson) Rydb. -- not accepted
  Wahlbergella montana (S. Watson) Rydb. -- not accepted
  Wahlbergella parryi (S. Watson) Rydb. -- not accepted
  Wasatchia kingii (S. Watson) M.E. Jones -- not accepted
  Washingtonia sonorae S. Watson -- not accepted
  Zanthoxylum clava-herculis var. fruticosum (A. Gray) S. Watson -- not accepted
  Zapoteca formosa var. schottii (Torr. ex S. Watson) H.M. Hern. -- accepted -- Schott's stickpea
  Zea canina S. Watson -- not accepted
  Zephyranthes atamasca var. treatiae (S. Watson) Meerow -- not accepted -- Atamasco lily
  Zephyranthes atamasco var. treatiae (S. Watson) Meerow -- not accepted -- Atamasco lily
  Zephyranthes treatiae S. Watson -- accepted
  Zigadenus fremontii (Torr.) Torr. ex S. Watson -- not accepted -- Fremont's deathcamas
  Zigadenus fremontii var. fremontii (Torr.) Torr. ex S. Watson -- not accepted -- Fremont's deathcamas
  Zigadenus nuttallii (A. Gray) S. Watson -- not accepted -- Nuttall's deathcamas
  Zigadenus paniculatus (Nutt.) S. Watson -- not accepted -- foothill deathcamas, sand-corn
  Zigadenus venenosus S. Watson -- not accepted -- death camas, meadow deathcamas
  Zigadenus venenosus var. venenosus S. Watson -- not accepted -- meadow deathcamas
  Zostera pacifica S. Watson -- not accepted -- Pacific zostera
  Zygophyllidum biforme (S. Watson) Arthur -- not accepted
   

A gray bar